Review on Vmotor Adjustable C Spanner Hook Wrench Tool - 3/4-2 inch (19-51mm) - Chrome Vanadium by David Silva

Useful as a castle nut wrench for AR. I would have preferred the Magpul Armorers key but for the price it worked. Just make sure you keep it in the groove with your hand or it will slip off and ruin your finish. Update: Doesn't fit all AR castle nuts, for my purposes I spliced them with a star (3 to 2). Completely unsuitable for SB Tactical PDW. Hardly works like an adjustable wrench on anything other than steel. The tab that must make contact with the castle nut slots is cast and not machined at all. It's worth taking a file and giving it a little more verticality. Or don't waste your money and invest your $15 in a proper gunsmith wrench like I should have.