AR-15 Mag Well Vise BlockBolt It To Your Bench or Clamp It In Your Vise! The AR-15 Mag Well Vise Block holds your AR-15 safe and secure for service and cleaning. Just slide your AR-15 over the Mag Well Vise block... It fits right into the Magazine well and locks in place using the magazine lock on your receiver. Mount the base to your work bench. Or, the Vise Block itself can be removed from the base and clamped in your vise. Built-In Hammer Stop - Real handy for doing trigger work... The Hammer stop let's you dry-fire without damaging the lower receiver. Heavy Duty, But Gentle - Solvent resistant polymer is durable but non-marring.