Model: SCRAAM-20 Top flat picatinny rails, other three sides key hole cutout Overall Length: 312mm (12.3 inch) Weight (net): 385g (13.6 ounce) Inside Dia 46mm (1.8 inch) Lower rail style with CNC procedure One piece style more accurate Upper rail is extended over the barrel nut for a 'no-gap' monolithic look Light weight in precision Easy and quick installation High quality aluminum alloy in durable black matte finish With tools, 2 pcs 3" detachable picatinny rails and gift box Shock proof can be used on real fire caliber Vector Optics and made in China under our strict quality control