Real Avid Lug-Lok Vise Block
The upper receiver was not designed to be put in a vise. Yet common upper receiver vise blocks can apply enough inward pressure to deform the upper when torqued. Real Avid decided to move the upper support to the strongest part of your gun - the star chamber.
Just secure the Lug-Lok Vise Block in your bench vise at an optimal angle for the work you need to do. The non-marring, aircraft-grade aluminum rod slides through the upper receiver and into the star chamber. Precision milled lugs solidly fit into the star chamber. And the exclusive Lock Knob locks it all into position while in use.
Now, you've got a rock solid foundation with no external pressure on the upper. Go ahead and apply all the torque you need to break free that stubborn barrel nut or crusty suppressor. Get smart about the way you work on your firearm with the Lug-Lok Vise Block. It's the strongest, safest, most secure upper vise block you'll find for you AR15.
Features:
Rod fits securely into star chamber
Torquing barrel nut applied pressure to steel star chamber/protects upper receiver
Lock knob keeps the upper receiver from sliding while working
Vise pins adjust to lock upper receiver at optimal working angle | 
