Features: Fits dovetail 11mm rails. Dovetail rails extension. Can be used to convert 11mm to 20mm. Specification: Top Rails Full Length:100mm Dove rails length:75mm Weight:65g Gross Weight:90g Height:13mm Top Picatinny rails width: 20mm Bottom dovetail rails width: 11mm Material: aluminum alloy Color: Black Package Included: 1 x Dovetail Rails 11mm to 20mm Adapter (DO NOT included Allen Key,Long screw,Stop pin screw )