Kit includes a modular AR15/ M4 upper receiver block for performing work on your upper receiver. Heavy duty barrel wrench works with MIL-SPEC barrel nuts for installation or removal of the barrel and free float handguards with the same hole spacing. A 5/8 wrench on the opposite end for 5/8 muzzle brakes and flash suppressors. The wrench is also ½ and 3/8 drive ratchet and breaker bar compatible. Heavy duty castle nut wrench for M4 MIL-SPEC and commercial type collapsible stock buffer tubes. A 3/4 wrench on the opposite end for the installation/removal of A2 buffer tubes. The wrench is also ½ and 3/8 drive ratchet and breaker bar compatible. Front sight adjustment tool that works with both A1 (5 prong) and A2 (4 prong) type front sight posts for zeroing your iron sights. R-15/ M4 GI handguard removal tool that works with rifle, carbine, and mid-length handguards. Magazine well lower receiver vice block.