Description: Military picatinny rails for the installation of flashlight， laser and red dot scope etcLength: 170mm (6.7 inch)Weight (net): 320g (11.3 ounce)Outside Dia 45mm， Inside Dia 40mm (if installed on caliber)Lower rail style with CNC procedureCan be splited two parts for easy installationLight weight in precisionHigh quality aluminum alloy in durable black matte finishShock proof can be used on real fire caliber Package Content: > 1 x Quad Rail System> 1 x Wrench