Tiger Rock Mil Spec Collapsible Standard Version Stock Body AR-15 Black Small. The stock is made from extremely tough fiberglass-reinforced injection-molded nylon that stands up well to the elements. It features a black matte finish with a built-in swivel. Specifications for Tiger Rock AR-15 Mil Spec Collapsible Standard Version Stock Body: Manufacturer: Tiger Rock Gun Model: M4 AR-15 Stock/Brace Material: Plastic Gun Type: Rifle Fabric/Material: Reinforced Plastic Composite Features of Tiger Rock AR-15 Mil Spec Collapsible Standard Version Stock Body M4 MIl-SPEC 6 position buttstock Fits standard MIL-SPEC 6-Position buffer tubes Metal sling loop/attachment installed Package Contents: Tiger Rock AR-15 Mil Spec Collapsible Standard Version Stock Body What firearm models does the manufacturer say Tiger Rock AR-15 Mil Spec Collapsible Standard Version Stock Body is compatible with? The manufacturer suggests that Tiger Rock AR-15 Mil Spec Collapsible Standard Version Stock Body is compatible with AR-15 M4Tiger Rock ST003M: Mil Spec Collapsible Standard Version Stock Body AR-15 Black Small