Just bought one of these for about £14.00 and a shim set for £7.00, have to say its a better fit and more secure than the factory version, tightens with a twist of a small lever, although I've left it in place, also has a picatinny/weaver rail on the side for fitting additional IR, this is removable. It has a 45mm ID and the shim set is better than any others I've used as the all have a lip to they remain butted up to the face of the adapter




