JMac Customs 4.5mm Folding AK Stock Pin Black Nitride Black. Barrel must extend at least 1.32'' from the gasblock This is designed to be permanently attached to a 14.5 inch barrel and adapt to KeyMo compatilble suppressors We recommend this muzzle device be professionally installed on our 14.5'' barrel by one of our Kalashnismiths to ensure alignment. Specifications for JMac Customs 4.5mm Folding AK Stock Pin: Manufacturer: JMac Customs Color: Black Finish: Nitride Gun Make: Kalashnikov Fabric/Material: 4140 heat treated steel Length: 4.5 mm Features of JMac Customs 4.5mm Folding AK Stock Pin 4 Port Muzzle Brake with KeyMount Package Contents: JMac Customs 4.5mm Folding AK Stock Pin JMac Customs FSP-4.5: 4.5mm Folding AK Stock Pin Black Nitride Black