American Built Arms Company AI Spec Magazine .308 Black Small. They are manufactured from high quality polymer and uses a tempered steel spring. We put our magazines through vigorous testing. We have used high quality strength polymer with a high glass content to ensure durability and strength. Although not unbreakable we have driven over these magazines with cars and trucks which did not break them. Specifications for American Built Arms Company AI Spec Magazine: Manufacturer: American Built Arms Company Color: Black Fabric/Material: high quality polymer Magazine Capacity: 10 Round Gun Model: AICS (Accuracy International Chassis System) Quantity: 1 Condition: New Size: Small Package Contents: American Built Arms Company AI Spec Magazine What firearm models does the manufacturer say American Built Arms Company AI Spec Magazine is compatible with? The manufacturer says that American Built Arms Company AI Spec Magazine is compatible with AICS (Accuracy International Chassis System)American Built Arms Company AISMAG308-10RD: AI Spec Magazine .308 Black Small