Ruger 10/22 Scope mount fits the pre drilled holes on top of your 10/22 rifles receiver, easy to install Scope mount is dual purpose base for the Ruger 10/22 it can take both Weaver and 3/8" dovetail rings. Rail is 4.76" Finsh Black. Limited Lifetime Warranty. Comes with all mounting hardware made for Ruger 10/22.