The Picatinny rail
The Picatinny rail was originally for mounting scopes atop the receivers of larger caliber rifles, but, once established, its use expanded to other such accessories as tactical lights, laser aiming modules, night vision devices, reflex sights, foregrips, bipods, and bayonets. Because of their many uses, Picatinny rails and accessories have replaced iron sights in the design of many firearms, and they are also on the undersides of semi-automatic pistol frames and grips. Their usefulness has led to them being used in paintball and airsoft.
Options include:
