Scope rail fits; Mossberg shotgun 500, 500A, 505, 510, 590, 590A1, 535, 835, 930, 935, 88 in 12/20 gauge, with factory drilled and tapped receivers. This alloy mount is low profile with see thru design which allows use of front sight bead. Mounting screws and allen key included. Select which colour you want. #1) Black #2) Silver