Fiber reinforced polymer build as an upgrade for the product's life span. Adjusted hand placement and reduces recoil. Accessory is universal that work the same as the 5.56/.233 rifles and 7.62/.308 rifles handguards. Scout mount is measured at 1.25 that puts the user at an advantage against other competitors. Product easily mounts onto threaded fasteners for quick placement. In the Box 1X Rail Hand Stop Specifications: Manufacturer Centurion Arms Model CMR Hand Stop Material Fiber Reinforced Polymer California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov