This is a small (18mm) inline filament cutter that mounts to a bowden tube. It utilizes 2 springs from click pens (3.5mm ID x 20mm long) and a 9mm snap blade section as well as two PC4-M6 fittings for parts. The threads are M6x1, I cleaned mine up with a tap after printing but it wasn't necessary. It needs to be printed with a .12mm layer height because of the fine detail, although I have not tried larger.

Parts List 4x20mm Spring out of a pen or (https://amzn.to/4fu72GS) x2 9mm Snap Off Blades (https://amzn.to/3BPebno) x1 PC4-M6 Bowden Tube Fitting (https://amzn.to/4gnzEmH) x2