Check the listing for details. .40CAL 10MM 9/16x24 Muzzle Brake Black Ano, 10-degree, for Glock 17 width slides. Color: Black, Condition: New. Listed at 36.00 USD. YOU NEED A THREADED BARREL WITH 9/16"-24 THREADS TO USE THIS ITEMThis is a high quality, aluminum muzzle brake compensator. It is made in the USA (Minnesota actually). Features include: 10mm and .40 calibervanes angled 10 degrees back to match some slide geometries threaded for 9/16"x24 tpi right handed threadsLoosen and tighten with 2 screws for easy on/easy off COUNTER-BORED: this feature on the slide facing side lets the brake get closer to the slide to make the gap smaller! (see picture of the side view)width is sized to match the Glock 22, 23, and 24 (1.00" wide - measure yours to see if it will match)flush with the top of the glock slidedistance (or gap) from the front of the slide depends on your particular barrel but is reduced by up to 1/16" because of the Counter-bore.add roughly 0.89" to the length of the barrel (however far out yours sticks)Made of 6061 AluminumAnodized black, hard coat type IIIheld on with #6-32 x 3/8" socket head cap screws tighten set screws to 10-12 inch pounds NEW VERSION!! Not Pictured. Slot is moved closer to the screw heads, so more threads to engage when tightening to hold on the barrel. Big Improvement! This reduces felt recoil for competition, or duty. Works better with higher grain/higher power loads (they have more gas to push back against the brake with). In some cases, very light gamer loads will not cycle the action unless springs are changed out. Set screws are tightened with a 7/64" allen wrench. On screws this small about 10 inch pounds is all the tighter you want to get them.