This is a TacStar Side Saddle, model 1081029.
Ultra-rigid" this innovative lightweight aluminum unit straddles both sides of the receiver and is crafted with a non-glare anodized finish. The top Picatinny rail can mount a variety of accessories" yet is designed to sit just high enough to allow continued use of the shotgun's bead sight.
Features:
Billet Aluminum
Raised Picatinny Rail
Six Shell Sidesaddle