This is an unique Weaver to Weaver mount adapter. It lets you mount two Weaver rails back-to-back. For example, If you have a stockless airsoft shotgun with top Weaver rail, you can mount it to the bottom of an quad-rail airsoft assault rifle. Great for airsoft and paintball fun! This adapter will also work for Picatinny rails and NATO accessory rails. You will also need a #6-32x1-1/4" screw and a #6-32 nut to fasten this mount to accessory rails. The screws and nuts are not included, but can be easily sourced from your local hardware store (e.g. Home Depot, Lowes, etc.). Airsoft equipment used for illustration of this Weaver Rail to Rail Adapter are not included. WARNING: Although you can use this mount adapter on your real firearm, we have never tested it on a real firearms before. We do not know if the firearm heat/recoil will or will not damage it. Use it with real firearms at your own risk.