Works with LR308 and AR10 308 barrels and receivers; Ultimate tool for barrel nut installs; Excellent for removing stubborn/seized barrel nuts without damaging upper; Designed for muzzle device installs and will not damage index pin; Can be used to install forward assist/port door cover; Compatible with forged and billet LR308 and AR10 upper receivers; Machined from 4140 Ordnance grade steel; Durable Black Oxide finished for years of use; Will not mar or damage exterior of upper receiver; Receiver mounted sights can be left installed