The New GG&G Slim-Line USP M3/M6 Adapter is a low profile lightweight aluminum adapter that easily slips onto the existing USP light rails. The rail fits tight enough to retain zero of the Streamlight M6 laser. The New GG&G Slime-Line USP M3/M6 Adapter is machined from 6061 T6 aircraft-grade aluminum alloy using modern CNC machinery. It is then hard-coat anodized matte black per mil spec.