This is a cutting assistant is an angle control to your cuts of your EVA foam. this cuts have 3 setting. :90 degree or straight cuts :60 degree or angled cuts :45 degree for angled cuts

90 degree cuts These are the type of cuts you need for a straight and clean join between two 90 degree EVA foam.

60 degree Cuts for those cuts whose need to be bent in a 60 degree fashion.

45 degree cuts For those you need bent in a 90 degree bend

2 concave parts to put your finger to guide the knife along a path

stripped underside so its smoother to move (print with raft)

(I'm overdoing this detail summary? Ill stop)