Hawke Two-Piece Adapter Base 3/8" to Picatinny 6" Rail (153.5mm)(22400)Hawke Sport Optics 3 8"(9 10mm) to Weaver Base Adapter 2 Piece Matt Black HM17013 Hawke Sport Optics Universal Weaver Base allows you to mount Weaver style accessories to your firearm. Designed to firmly hold the scope in position. Perfect for converting a 3 8" standard rail to a Weaver rail. Having the extended rail allows for scopes or red dots to be mounted further down the barrel for that perfect eye relief. Mounts to 3 8" or 9 10mm rails Overall