This fast attach is all steel (not aluminum) and fits 5/8 x24 barrel threads that are usually found on AR10s, 308s, etc with 7.62 ammo. The external threads are 13/16" and fits all of our filter kits (the 5", 7" and 10" kits). It assists in speed cleaning since you can screw the tube on & off quickly. It DOES NOT come with a 5/8 steel crush washer (sorry). This fast attach has three large discharge ports on the main body and six micro-ports for top discharge (which compensates for muzzle rise). All threads are PARELLEL threads, so your rifle threads are never damaged no matter how many times you remove or install. The coating is black oxide which helps in resisting corrosion.
Add a couple at this killer price, they make great gift for a friend or your future rifle collection.