A super sharp, sturdy, fixed blade razor knife, modeled to fit Outdoor Edge 3.5" replacement blades. I had one of these knives years ago but lost it, and I still had 6 spare blades for it. These things are ridiculously sharp, and I wanted to put them to good use. A 6 pack of these blades comes in at just under $10 - Amazon link below The white is printed in 3D Universe white PLA, and the black is the 3D Universe black ABS. A .2mm layer height gives more than good enough prints on a regular Ender 3 Pro, but I did use my insulated chamber for the ABS parts because they will warp without.

https://www.amazon.com/Outdoor-Edge-Razor-Replacement-Blades/dp/B00DOML9AG/ref=sr_1_2?dchild=1&gclid=Cj0KCQiA-bjyBRCcARIsAFboWg3p41bBWVVm8rQOwWTQQpBhj2vd6vSsJxeHnbA-9k7FtRtZcWC-2BgaAgaXEALw_wcB&hvadid=174261146094&hvdev=c&hvlocphy=9004669&hvnetw=g&hvqmt=e&hvrand=3909081834851254390&hvtargid=aud-835997443427%3Akwd-42215707058&hydadcr=9383_9621528&keywords=outdoor+edge+blades&qid=1582237475&sr=8-2