Single Flexion
retrofit kit for single extruder

(6 customer reviews)


Developed by the inventor of Ninjaflex

Drop-in 3D printer extruder retrofit kit for i3-style printers like the Wanhao Duplicator i3 (and PLUS). Print with flexible materials, higher resolution, and fewer failures. Also prints ABS and PLA better than your stock extruder.

*Does not include stepper motor.

SKU: 5121SKU0001 Category:


3D printer extruder retrofit kit for single-extruder direct-drive machines, such as the Wanhao Duplicator i3 (and PLUS), Monoprice Maker Select, or Makerbot rep2 (see pulldown menu). The Flexion extruder will allow full-speed printing of flexible filaments and improved accuracy printing with PLA and ABS. The precision machined components allow your printer to push on filament harder, achieve high pressure in the nozzle, and control of feed rates very closely. The self-cleaning drive will keep your long prints from failing due to a clogged drive. Works will with Ninjaflex, Filaflex, flexible PLA, TPU, TPE ultra-flexible filament down to 50 Shore A, and all the standard rigid filaments like ABS and PLA.


The Flexion Extruder uses a high-stiffness lever to compress the filament. The compression is controlled with a cam and an adjust screw, rather than the traditional spring. This allows more tension and more precise control of the tension. To learn more about the benefits and drawbacks of this system, please read our blog post about it.

This kit requires you to disassemble your printer’s extruder and reinstall this upgrade. Detailed instructions on this process can be found on our support page.

Single explode



Additional information

Weight 2 oz
Dimensions 3.5 × 4.5 × 1.25 in
Works with

i3 printers. Designed for 2x M3 mount at 31mm spacing (Wanhao Duplicator i3 (and PLUS), Monoprice Maker Select (and PLUS) ). If you have a single M6 mounting screw, such as with HICTOP, make a note on your order for a special mounting block. Will also work with Folgertech printers, or other printers that mount to the back of the extruder motor. See Support page for information on retrofitting to your printer.


Mounting block
Tensioning arm with idler and cleaning brush
Adjustment cam
Drive gear
Feed barrel
Heater block
Insulation for heater block
3 nozzles – 0.3, 0.4, 0.5 mm orifice
Adapter shim to allow 6mm and 0.25" heater cartridges
2 PTFE feed tubes (one can be used an an inlet tube)
Spare cleaning brush
All mounting hardware
6mm and 7mm wrench for installing nozzles
"Flexion inside" quick-guide sticker

Note: does not include stepper motor or motor mounting screws

6 reviews for Single Flexion
retrofit kit for single extruder

  1. Johny007 (verified owner)

    I LOVE IT. I didn’t print much with original Wanhao extruder, I had to print slowly and results sometimes weren’t very satifying. My prints are very consistent and I print twice faster than before. I haven’t tried flexible stuff, but I don’t suspect any problems there since PLA works so great.

  2. Ira Sather-Olson (verified owner)

    I purchased this extruder to use on my employer’s MakerBot Replicator 2 3D printer, and the results have been stellar. With just a few tweaks in the settings of the Makerbot software interface, I’ve been able to get quality prints on a consistent basis. Best of all, this extruder hasn’t clogged or given me any issues. I highly recommend it.

  3. Greg Whitmore (verified owner)

    WOW! I modded an Anet A8 to use this Flexion extruder and couldn’t be happier. Prints amazingly in Flex materials and also Raptor PLA prints much better with the Flexion. Only wishing I bought the Dual extruder kit instead.

  4. Cory Campbell (verified owner)

    Im using this extruder on a Monoprice Maker Select Plus (Wanhao i3 Plus). So this thing prints and it prints very well! Ive printed with PLA, Ninjaflex and PETG so far. Follow the instructions that Diabase has documented and you will be good to go. As far as Ninjaflex goes, I used the file Diabase had listed for Simplify3D and it seemed to print perfectly except for one thing, Ninjaflex sticks really well to PEI. Sticking so well that I screwed up a few prints. FYI use hairspray on the PEI with Ninjaflex. I also need to tell you about the service… I screwed up my order and I emailed Diabase for help. I sent the email on a Sunday and got a reply back from Austin the same day! He helped me solve the problem and I am very grateful. Thanks for the great product and support!

  5. Simon Reynolds (verified owner)

    Installed on a forge 3d (Wanhao rebrand) and what an unbelievable difference in quality and reliability. The price is well justified as I’ve greatly minimized waisted material in failed prints and time clearing clogs. (In fact I’ve had none) Installation was straight forward (spent more time dropping my tools than working on the install) and customer service were prompt and informative. Oh… and it looks cool.

  6. Bigjon

    I recently bought the Flexion Bundle kit.I must say the Flexion Extruder is the best one out there. Much better prints than the stock one Monoprice makers select v2. It prints nylon,tpu, flexpla. plain pla with a few minor adjustments. the speed you need to adjust a little slower works for me. You just need play around with your settings. Over all I give it a A++++. Great customer support. A must upgrade!!!.

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