LP HUB (1.375x24tpi) adapter 
 
Compatible with Plan B/Cherry Bomb type muzzle devices
Machined from 17-4 stainless steel
Black nitride finish
Adapts to SilencerCo BRAVO HUB or any other 1 3/8 x 24 threaded muzzle devices
Install with a 1.5" spanner wrench
 
Diameter: 1.5"
Weight: 2.5oz.