This is a case for the Pocket Operator series. It uses snap fits and has removable supports. The Pocket Operators are great for noodling on the go and these cases help protect them from damage plus they look kinda cool.
The Top Snap piece is named A, the Bottom Snap is B, Front Cover is C, and Button cover is E.
'A' and 'C' work best with single perimeter, and 10% infill.