Looks like one of these
http://www.sinclairintl.com/shooting-rests-bipods/bipods/monopods/bipods-adapters/sinclair-3rd-generation-f-class-bipod-prod44699.aspx
Type: Posts; User: sparky1000
Looks like one of these
http://www.sinclairintl.com/shooting-rests-bipods/bipods/monopods/bipods-adapters/sinclair-3rd-generation-f-class-bipod-prod44699.aspx