What is it for? Search youtube for "plastic bottle cutter rope"
https://www.youtube.com/results?search_query=plastic+bottle+cutter+rope

Remix of bottle cutter by Szalat
*added version for blades 10mm width (works best)

• decreased print volume and time
• increased slots width to easier accomodate the blade
• added metal washer slot to avoid cutting the bottom : major improvement, increased lifetime by many orders of magnitude

Slide an appropriately sized metal washer or small coin into the slot to create a metal base preventing the bottle to cut into the PLA. Washer dia 18-20mm, thickness 1-1.5mm works best. Freecad source included for easy adjustment of washer size. Insert blade with the sharp edge facing the longer empty space, washer or small coin on the opposite side of the sharp edge. Cutting with the bottle supported by a 5mm wedge on the other side after start helps keep it vertical.

Cheers!