The screws that are included with this mount require a 5/64'' allen wrench for installation. Mounting Hardware is Included 6-48 X .313"" Overall Length 8-40 X .313"" Overall Length 8-40 X .335"" Overall Length This mount has a bottom radius of .670"". There should be a slight gap at the top of the radius between the receiver and the mount when mounted. The two spreads on this mount measure .500""-.505"" and .8625"" which should fit the receiver ring on the following guns: Common Applications: Shotgun: Mossberg 500, 590, 835, 930, 935 Pre '97 Mossberg 500 Mfg: Egw
