Flex FX4221-Z Review: The Best Value Package in Cordless Trim Routers?

Flex FX4221-Z cordless router review
The Flex FX4221-Z is a 24V brushless trim router that offers premium features at a competitive price.

 

The Flex FX4221 cordless router looks remarkably similar to the market-leading DeWalt DCW600B. That’s no coincidence—Flex clearly benchmarked the DeWalt (one of the best routers in the segment) and asked “how do we make this better?” The result is a router that improves on DeWalt’s design in almost every way while costing $20 less and including a significantly better accessory package. But is the Flex 24V router just a DeWalt knockoff, or does it stand on its own merits? After extensive hands-on testing including aggressive power tests in hardwood, I’ll help you decide if the Flex FX4221 is the right router for your shop.

Flex FX4221: At a Glance

Best For: Woodworkers who want DeWalt-level performance with better value and aren’t locked into an existing battery platform

Price (MSRP): $199 (tool only), but can often be purchased for less

Bottom Line: The Flex FX4221 delivers excellent power, features a brilliant single-ring adjustment system, and includes the best accessory package in its class with an edge guide, dust chute, second base, AND centering cone. At $199, it offers significantly better value than the DeWalt while matching its performance.

 

👉 Check current price on the Flex FX4221 here

 

Flex FX4221 Specifications

SpecificationDetails
Model NumberFX4221-Z (also FX4221)
Voltage24V
Motor TypeBrushless
Speed Range16,000 - 31,000 RPM
Variable SpeedYes
Horsepower1.5 HP
Collet Size1/4"
Weight (tool only)3lb 9oz
Base TypeD-shaped
LED LightYes
Spindle BrakeYes
Plunge Base AvailableYes (sold separately)
Included AccessoriesEdge guide, dust chute, second base, centering cone

What’s in the Box?

This is where the Flex shines. For $199, you get:

  • FX4221 router (tool only)
  • Edge guide with quick-attach mechanism and extending stability arms
  • Dust chute
  • Second base for template routing
  • Centering cone
  • 1/4″ collet wrench

 

The edge guide is particularly impressive with extending arms similar to expensive aftermarket guides. The centering cone (typically $15-30 separately) is crucial for template work and using round bases against straight edges—exactly the kind of accessory pros appreciate not having to buy separately.

Compare this to the DeWalt at $219 that includes only a wrench, and the Flex’s value proposition becomes clear.

Edge guide attachment installed on the Flex FX4221 trim router
The included edge guide expands the Flex router’s usefulness for straight cuts.

 

Extra router base and centering cone included with the Flex FX4221
Flex includes a second base and centering cone, adding value to the kit.

 

Understanding Flex: Not a Knockoff Brand

Before dismissing Flex as a cheap DeWalt imitation, understand the company’s history. Flex started in Germany in 1922 and became part of the Chervon brand in 2013 (which also owns Skil). Flex targets professionals while Skil aims at hobbyists. This is a legitimate tool manufacturer with nearly a century of history, not a fly-by-night knockoff operation.

The similarity to DeWalt is intentional benchmarking, not counterfeit copying—and Flex improved the formula in key ways.

Flex FX4221 and DeWalt cordless trim routers compared side by side
The Flex router is nearly identical in size to DeWalt’s popular cordless trim router.

 

Design & Ergonomics

The Flex FX4221 is nearly identical in size to the DeWalt DCW600B—the motors are almost interchangeable (though I tried, and they won’t fit in each other’s bases). At 3lb 9oz without battery, it’s actually 2 ounces heavier than the DeWalt, making it the heaviest router I tested. But the weight distribution is good, and it doesn’t feel cumbersome in use.

Grip Design

The large rubberized grip provides secure, comfortable hand placement. The grip works well for medium to large hands.

Power Switch: A Major Improvement

This is one of the key areas where Flex improved on the DeWalt. The DeWalt’s rubber-covered power button is not always the easiest to operate and is difficult to read. Flex replaced it with a large, easy-to-press button that’s clearly labeled and simple to use.

Push-button power switch on the Flex FX4221 cordless trim router
The top-mounted power button is easy to reach and works well for one-handed operation.

 

Worried about accidental starts? Flex included a spindle lock function (similar to Bosch) that prevents the router from powering on when engaged. This doubles as a safety feature and makes bit changes easier.

Spindle lock switch on the Flex FX4221 cordless trim router
The spindle lock simplifies bit changes without needing multiple wrenches.

 

Base Design

The D-shaped base is large, and identically sized to the DeWalt’s. The square side provides a place to put your fingers to secure the router especially when doing things like edge profile work, while the rounded side is perfect for running along straight edges.

Flex and DeWalt cordless trim routers with similarly sized D-shaped bases
Both routers use large D-shaped bases, contributing to stability and control.

 

The Adjustment System: Same Excellence as DeWalt

Flex uses the same adjustment ring system as DeWalt, and it’s one of the best in the category.

How It Works

  1. Unfasten the latch
  2. Rotate the adjustment ring to desired depth
  3. Re-fasten the latch

 

That’s it. No separate macro/micro controls, no locked/unlocked positions to remember. Just turn the ring until you reach your desired depth.

Measurement System

The measurement ring provides clear visual feedback:

  • Each tick mark represents 1/64″
  • One complete rotation equals 1/2″

 

This makes precise, repeatable settings easy to achieve and document.

Adjustment scale on the Flex FX4221 cordless trim router
The Flex adjustment scale is easy to read and works in combination with the adjustment ring.

 

The Trade-Off

When covering significant distance (changing from shallow to deep cuts), you’re turning that ring for a while. Routers with dedicated macro buttons cover ground faster. But for precision work where you’re making small adjustments, this system is excellent and intuitive.

Power & Performance

The Power Test

I stressed-tested all routers by routing a 1/2″ × 1/2″ rabbet in 2 feet of dense sapele hardwood.

Flex FX4221 Result: 11 seconds with zero shutdowns (2.5ah battery)

This is impressive, placing just one second behind the DeWalt and Bosch. For context:

  • Bosch: 10 seconds (4ah battery)
  • DeWalt: 10 seconds (5ah battery)
  • Flex: 11 seconds (2.5ah battery)
  • Milwaukee: 13 seconds (2ah battery)
  • Metabo HPT: 13 seconds
  • Ridgid: 13 seconds (4ah battery)
  • Makita: 21 seconds (2ah battery)
  • Ryobi: 38 seconds (2ah battery)

 

Critical Context: The Flex used a 2.5ah battery—significantly smaller than DeWalt’s 5ah battery. Given the smaller battery, the Flex might have matched or beaten the DeWalt with equal power. The 1.5 HP rating (highest among tested routers) supports this.

Flex FX4221 cordless trim router cutting a rabbet in hardwood
In hardwood testing, the Flex router handled rabbet cuts with ease.

 

Real-World Performance

The Flex FX4221 handles all typical routing tasks with confidence:

Edge Profiling: Powers through roundovers, chamfers, and decorative profiles in hardwood. The 1.5 HP motor provides consistent speed under load.

Template Routing: The included second base and centering cone make template work easy. The router tracks smoothly with bearing-guided bits without speed drop-off.

Dado Cuts: Has sufficient torque for straight-bit dados in 3/4″ hardwood.

The variable speed control (16,000 – 31,000 RPM) offers excellent range for different materials and bit sizes.

Flex FX4221 vs the Competition

Flex FX4221 vs DeWalt DCW600B

 

DeWalt DCW600B cordless trim router on workbench
The DeWalt DCW600B remains one of the most refined cordless trim routers available.

 

This is the most important comparison. The Flex appears directly benchmarked against the DeWalt.

Where Flex Wins:

  • Price: $199 vs $219
  • Accessories: Edge guide, dust chute, second base, AND centering cone vs just a wrench
  • Power Switch: Large, easy-to-press button vs frustrating rubber-covered switch
  • Spindle Lock Function: Prevents accidental starts when engaged
  • Value: Dramatically better—$20 less with $50-75 worth of additional accessories

 

Where DeWalt Wins:

  • Battery Ecosystem: DeWalt’s 20V Max platform is more extensive
  • Brand Recognition: Decades of router manufacturing expertise
  • Availability: More widely stocked at major retailers

 

Verdict: If you’re locked into DeWalt’s battery platform, switching is not necessary. But if you’re not committed to a battery ecosystem or can handle batteries from two brands, the Flex offers dramatically better value with virtually identical performance.

Flex FX4221 vs Milwaukee 2723-20

 

Milwaukee 2723-20 M18 Fuel cordless trim router on workbench
The Milwaukee 2723-20 is a dependable cordless trim router with strong ergonomics.

 

Where Flex Wins:

  • Power: 11 seconds vs 13 seconds
  • Adjustment: Single-ring system is simpler than button + dial
  • Base Size: Larger D-shaped base vs Milwaukee’s round base
  • Accessories: Includes centering cone (Milwaukee doesn’t)
  • Same Price: Both $199

 

Where Milwaukee Wins:

  • Weight: 3lb vs 3lb 9oz
  • Ergonomics: Better grip design with less bulk
  • Battery Ecosystem: M18 platform is as extensive as any
  • Adjustment Feel: Some prefer Milwaukee’s traditional design

 

Verdict: At the same $199 price, it depends on priorities. Flex offers more power and better accessories. Milwaukee offers better ergonomics and a more established battery platform. Both are excellent values.

Flex FX4221 vs Bosch GKF18V-25N

 

Bosch GKF18V-25 cordless trim router on workbench
The Bosch GKF18V-25 is the lightest and most refined cordless trim router tested.

 

Where Bosch Wins:

  • Weight: 2lb 8oz vs 3lb 9oz—over a pound lighter
  • Ergonomics: Molded finger grips reduce fatigue
  • Precision: Micro adjustments are more precise
  • Safety Features: Drop detection

 

Where Flex Wins:

  • Price: $199 vs $219
  • Adjustment Simplicity: Single ring is more intuitive than Bosch’s locked/unlocked system
  • Accessories: Includes centering cone (Bosch doesn’t)

 

Verdict: Both are great routers, but Bosch is lighter and more innovative — at $20 more. It may just come down to how they feel in the hand.  Larger hands may find the Flex more comfortable, while smaller hands may prefer the Bosch.

Flex FX4221 vs Makita XTR01Z

 

Makita XTR01Z 18V LXT cordless trim router on workbench
The Makita XTR01Z is a compact cordless trim router designed for Makita’s 18V LXT platform.

 

Where Flex Wins:

  • Power: 11 seconds vs 21 seconds
  • Safety: Spindle lock function (Makita doesn’t even have spindle brake)
  • Adjustment: Superior to Makita’s gravity-prone design
  • Base Design: Larger, more versatile D-shaped base
  • Accessories: Comprehensive package vs Makita’s edge guide only

 

Verdict: At the same $199 price, the Flex is dramatically superior unless you’re heavily invested in Makita’s battery platform.

Pros and Cons

Pros

  • Excellent power (1.5 HP)
  • Best accessory package (includes centering cone)
  • $20 cheaper than DeWalt with better accessories
  • Superior power switch design
  • Excellent adjustment system
  • Spindle lock function for safety and easier bit changes
  • D-shaped base provides good stability

 

Cons

  • Heaviest router tested (3lb 9oz)
  • Newer brand with less market presence than DeWalt/Milwaukee
  • Battery ecosystem less extensive than established brands
  • Large size may not suit smaller hands

 

Who Should Buy the Flex FX4221?

You’ll Love This Router If:

  • You want DeWalt performance for less money – Virtually identical size and power at $20 savings
  • You value accessories – The included centering cone, second base, and premium edge guide add real value
  • You’re not locked into a different battery platform – If you’re starting from scratch, or don’t mind having more than one platform, Flex offers the best value in the premium tier
  • You prioritize the power switch – The large button is vastly better than DeWalt’s
  • You want a large, stable base – The D-shaped base provides excellent control

 

Look Elsewhere If:

  • You’re locked into another battery platform – Platform compatibility matters more than marginal differences
  • Weight and fatigue matter significantly – Bosch (2lb 8oz) or Metabo HPT (2lb 9oz) are much lighter
  • You want the most established ecosystem – DeWalt and Milwaukee have more extensive 24V/20V/18V platforms
  • Brand recognition matters – Flex is newer to the U.S. market

 

See How It Compares

I tested the Flex alongside seven competing routers in a full head-to-head video. You can watch that comparison here:

FAQ: Flex FX4221 Questions

Is the Flex FX4221 any good?

Yes, the Flex FX4221 is excellent. It delivers power that rivals the DeWalt and Bosch, features the same intuitive single-ring adjustment system as DeWalt, and includes the best accessory package in its class. At $199, it costs $20 less than the DeWalt while including an edge guide, dust chute, second base, and centering cone. The Flex is a legitimate professional-grade router backed by a company with nearly a century of tool manufacturing history.

Is the Flex 24V trim router powerful?

Yes, the Flex 24V trim router is very powerful. With 1.5 HP (the highest rating among routers tested) and variable speed up to 31,000 RPM, it completed my demanding hardwood stress test in just 11 seconds—only one second behind the fastest routers (Bosch and DeWalt). Notably, the Flex achieved this with a 2.5ah battery while the DeWalt used a 5ah battery, suggesting the Flex might match or exceed DeWalt’s performance with equal battery capacity.

Does the Flex router come with a plunge base?

No, the Flex FX4221 does not come with a plunge base. However, Flex offers a compatible plunge base (FT421) sold separately that expands capabilities for mortising, inlay work, and stopped cuts. The FX4221 does include a second base plate for template routing that fits standard sized guide bushings, which is valuable for many applications.

Is the Flex router worth the price?

Yes, the Flex router offers exceptional value at $199. It delivers performance nearly identical to routers costing $20 more (like DeWalt and Bosch) while including a significantly better accessory package. The centering cone alone is worth $15-30 separately, and the premium edge guide with extending arms rivals expensive aftermarket options. If you’re not locked into another battery platform, the Flex offers the best value in the premium cordless router tier.

Who makes Flex power tools?

Flex power tools are made by Chervon, a global tool manufacturer based in China that also owns the Skil brand. However, Flex has German heritage dating back to 1922 and targets professional users, while Skil focuses on hobbyists. Chervon is a legitimate, established manufacturer. The Flex 24V platform represents a serious entry into the North American professional tool market.

Final Verdict

The Flex FX4221 delivers DeWalt-level performance for $20 less while including $50-75 worth of accessories the DeWalt doesn’t have. At $199 with an edge guide, dust chute, second base, and centering cone, it offers the best value in the premium cordless router tier.

The power switch is more functional than DeWalt’s, and the spindle lock function adds genuine convenience. The only real compromises are weight (3lb 9oz) and a less extensive battery ecosystem.

If you’re locked into DeWalt or Milwaukee platforms, I don’t think switching is necessary. But if you’re not committed to a battery ecosystem, the Flex FX4221 is hard to beat for value.

 

👉 Check current price on the Flex FX4221 here