The Midwest Industries AR-15 Upper Receiver Action Rod is the ultimate tool for barrel nut installs or removal. It is excellent for removing stubborn/seized barrel nuts without damaging upper. Designed for muzzle device installs, the action rod will not damage index pin. Can be used to install forward assist/port door cover. Compatible with forged and billet upper receivers. FeaturesMachined from 4140 Ordnance grade steelDurable Black Oxide finished for years of useWill not mar or damage exterior of upper receiverReceiver mounted sights can be left installedCan be installed horizontally or vertically in bench viseWorks with any standard M4/M16 barrel extension Notes:Not compatible with 9mm and rimfire barrelsNot compatible with DPMS G2 308Not compatible with SIG MCX VIRTUS / SIG MCX RATTLER