Ultimate Arms Gear M1 M-1 Carbine .30 Cal Rifle Easy Install 3.5" Rail Base Scope Sight Light Laser Mount Installs In Rear Sight Dovetail Without Permanently Altering Your Rifle Installation Requires You To Remove The Existing Rear Sight By Drifting It Out To The Right Side Of The Weapon Provides A Industry Standard 7/8" Weaver Picatinny Rail To Allow You To Mount A Scope, Scope Rings, Sight, Light Or Laser Length : 3.5" N.W. (OZ): 2.6 Made Of Black Anodized Aircraft Grade Aluminum