If you have a Remington 870(TM)/1100(TM) with a drilled and tapped receiver, then you absolutely must have the UTG Pro Model 870 Picatinny Rail Mount. The contoured bottom gives it a perfect fit and it has a low profile with see-thru design for use of the front bead sight. It is precision machined from aircraft grade aluminum with a matt black hard-coat anodized finish. It has a 6.1" extended length with 14 Picatinny rail slots for Dot Sights, Rear Sights, and flexible positioning of magnified optics for proper eye relief adjustment. Includes assembly screws and tools for simple and easy installation.