This fine looking tactical block for the TM Glock 17 is made by PDI-Japan... "We are making this block with Duralmin CNC all machined,NOT molding. So it's really sharp edge ! We put the 2 size rail on under mount.forward & rear is depth 2.35mm & the middle is depth 1mm.If you have some lights,please try them.Maybe you'll find a better points. If you use SURE FIRE X200A,Please use center rail of 3. It's the best fit."