JE Machine Tech AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo Black PS-ST2B+PS-BTM Combo. Specifications for JE Machine Tech AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo: Manufacturer: JE Machine Tech Color: Black Gun Model: AR-10 AR-15 Gun Type: Rifle Included Accessories: Standard Condition: New Buffer Tube Size: Mil-Spec Gun Make: AR Platform Finish: Type III Hard Coat Anodized Fabric/Material: 6061-T6 Aluminum Polymer Features of JE Machine Tech AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo Fits: AR10 / AR15 Mil-Spec Standard Carbine Adjustable Buttstock Spring Castle Nut Standard End Plate Package Contents: JE Machine Tech AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo What firearm models does the manufacturer say JE Machine Tech AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo is compatible with? The manufacturer suggests that JE Machine Tech AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo is compatible with AR-15 AR-10JE Machine Tech PS-ST2B+PS-BTM Combo: AR-10/15 M4 Mil-Spec Collapsible Buttstock Combo Black