Available to order $85.00 Gemtech, GM-45/Blackside Threaded Rear Mount Adaptor, 5/8X24 ThreadPitch, 300Blk 12194
Available to order $166.41 Gemtech GM-45 And Blackside-45 LID Piston Core For Glock 21 Factory Barrel, HK USP-T/USP-CT/45/45C Threaded M16X1LH TPI