Looks like a snapon ratchet...lol.It took me over a week to remove that bottom alternator bolt as it was siezed in the aluminum housing of the alternator.After a few days of spraying pb blaster and cussing(that seems to always help)it finally started to turn.I could get good leverage on it but it felt like it was going to snap the head off.Useing a torch to heat it was risky with all the oil baked on.