Probably the hardest piece to fit (so far). This one took a lot of trimming and piecing to get right, but I like the end product. This one is 6mm foam for the dark parts with 2mm foam (yellow) glued behind the cut-out to give it that recessed look. I won't be putting a "skin" over the dark parts to hide the defects, so this one is a true prototype: I'll use it as a pattern and cut two new pieces, one for my right thigh and one for my left. This one is just too rough -- especially on the edges -- to keep.