The EFR allows the use of a universal night sight (A/N PVS-22) on virtually any tactical rifle stock This mount is bedded into the forend of the rifle stock and allows for up to 7" of rail space due to its reversible top rail Made from 7075 aluminum alloy Weight: 7.4oz Should be installed by an armorer or gunsmith familiar with these type of firearms Mfg: Badger Ordnance