Check the listing for details. KIDD Silver Picatinny scope base for Ruger® 10/22®. Condition: New. Listed at 46.50 USD. -Aftermarket accessory for the Ruger® 10/22® -extends over the barrel 1 1/4" for increased eye relief -low base 1/4" height This KIDD scope base accessory will mount onto your factory receiver. Our scope base height is 5/16" (about 1/4") by 5 7/8" long and incorporates the Picatinny spacing system similar to the military spec. We chose the picatinny spacing so if customers have more rifles than scopes they can use the same scope ring spacing on more than one rifle. It works just like the Weaver style bases and rings you are accustomed to, only the slot spacing is identical for every mount made, no matter what gun it is attached to. Our low scope base extends over the front of the receiver for both function and fashion purposes. Function: the extension allows for greater eye relief. Fashion: the extended mount elongates the lines or contour of the receiver. The draw back is that our base doesn't work with rear sights Package includes: silver scope base, scope base 4 mounting screws short arm hex wrench