Made to exact Mil-Std 1913 Picatinny specifications by a US Govt Contractor, this rail comes with nylon risers that allow ample room for any tac-light or laser. This side rail fits on the P90 or PS90 USG by attaching to either side of the receiver using the existing threaded holes. Rails are precision machined from high grade aluminum and have a matte anodized protective finish. They also feature a clearance on the underside to allow for the uneven surface finish found on some receivers. You can use this rail in a low profile configuration by omitting the nylon risers. We're proud to stock what we've found to be the best rail design on the market, and to offer it to you at an honest price.