Description Aluminum Alloy Construction & very well built, Fit on all 20mm RIS Rail & Picatinny Rail Full metal construction. Low Profile Mount Base for G3 / MP5 Series Airsoft AEG. Hex Nut to tighten the base onto receiver top. 20mm Weaver mounting for scope attachment. Material: Aluminum Alloy. Length: 90mm (3.54″). Width: 20mm(0.78″) 1 x scope mount 1 x wrench