Hogue OverMold Free Float Forend AR-15/ M16 Carbine Length Slate Grey Universal. If it is approximately 12.5" it is a rifle length system if it is approximately 9" it is a Midlength and 7" for a Carbine length. 308 Rifles: There are two basic types of 308 "size" AR rifles often referred to as DPMS or Armalite "compatible" rifles. The parts magazines etc do not interchange. For an easy way to differentiate between the two styles of rifles look at the rear bottom of the upper receiver. A DPMS compatible rifle has a rounded edge while an Armalite has an angled edge. We offer a coupler nut for both types. DPMS #15060 with a 1 7/16"-16 TPI and Armalite #15061 with a 1 7/16"-18 TPI. Specifications for Hogue AR-15/M16 OverMold Free Float Forend w/ Grey Rubber Gripping Area: Manufacturer: Hogue Color: Slate Grey Fabric/Material: Rubber Gun Make: AR Platform Gun Model: M16 AR-15 Gun Type: Rifle Handguard Type: Free-Float Gun Rail: Round Included Accessories: Standard Country of Origin: USA Quantity: 1 Features of Hogue AR-15/M16 OverMold Free Float Forend w/ Grey Rubber Gripping Area: Forends work with all barrel types that will work with a standard Delta ring. Will not fit rifles with Piston Gas Systems. Will fit older model ARs and M-16s with triangular shaped handguard. Coupler Nut Torque specs: 30-80 ft/lbs Made of 6061 aircraft aluminum with a molded non-slip elastomer layer on the outside. Package Contents: Hogue AR-15/M16 OverMold Free Float Forend w/ Grey Rubber Gripping Area Hogue 15514: OverMold Free Float Forend AR-15/ M16 Carbine Length Slate Grey Universal