ONLY USE ALUMIDE. This rear riser is twice the height as the stock 10mm steel riser. I find it a bit imprecise and would suggest using the 10mm plasic and 10mm steel combined instead. I left it available in case you really want it. Requires an M6 x 1 tap and 2 set screws. Also, a bit stiff on the dovetails, depending on how the tolerances fall.