This is an extra deep, thin wall, 21mm hex socket, 1/2" drive.  Socket depth is about 10-3/4", plenty deep to reach into hard to access places such as handguard nuts.  (This fits 21mm hex nuts only, it does not fit special shaped nuts such as "Double D" nuts.)

I also have these in 3/8" drive, if that is what you prefer let me know and I can substitute at no charge, please send a message when you order.  I can make them in longer lengths upon request.

This socket is for hand torquing with a ratchet or breaker bar, it is not recommended for impact tools.

Please contact me if you have questions.

NOTE ABOUT SHIPPING:  USPS has sometimes been very slow with deliveries, sometimes taking up to 2 weeks!  We ship within 48 hours but once it is in the hands of USPS it is out of our control, please do not hold that against us.  If you have an urgent need contact us on how to upgrade to Priority Mail or UPS.  Thank you!