Recessed profile suppressor adapter compatible with Comstock, Rearden, and other common Plan-B muzzle devices. Currently the lightest recessed steel Plan-B HUB adapter on the market at just 2.1 ounces. Compared to the standard LPA, the RPA shortens the overall length of the suppressor system and makes a tighter handguard to suppressor gap. Allows for the quick attachment and removal of suppressors High strength 17-4 PH stainless steel Durable black nitride finish Standard 1.375-24 threads (also known as HUB or Bravo) for use on most rifle suppressors Has both 1-7/16" wrench flats and 1.5" spanner notches for easy installation and removal 0.18" added length 2.1 ounces Fitment note: The RPA places muzzle devices 0.40" deeper than our standard LPA. Please check your muzzle device and suppressor to ensure it will fit. Please contact us for more information. Some suppressor companies do not warranty their products when used on aftermarket mounts or muzzle devices. Always check bullet stabilization before attaching a suppressor and always use an alignment rod to ensure the suppressor system is set up correctly. Comstock Armory will not be held liable for injury, death, or damage resulting from the use or misuse of this product.