If you have taken your castle nut off in the past- this is good to get it on and off. - Ergo Grip Tactical CAR Stock Wrenches

Don’t purchase the remove your castle nut the first time, think your going to put your AR on the carpet and crack the seal... It won’t happen. But if you have had your nut removed before, even it it’s been staked, this will get it off and on in a hurry. Always use a gun vise when removing the castle nut initially from the factory.