The Viking Tactics Buttstock Adapter is designed specifically for the full stock AR-15. This adapter will fit all AR-15 full stock firearms as well as most shotguns from hunting to tactical, lever guns, and almost any bolt action with a standard size buttstock. The retaining strap is long enough to fit even larger stocks. When using a shorter stock, retain the end of the adjustment strap through the D-Ring onto the velcro. The retention buckle is a friction adapter, not relying on just velcro for retention. Made in the United States of America.