Made of 7068 Tenalum, these self timing muzzle brakes will reduce recoil without adding a lot of weight to your rifle. Large = .890" Body Diameter, 2.043" Length, 5/8-24 tpi, 22-30 cal Large timing collar tapers to fit best on Sendero and M24 contours Small = .890" Body Diameter, 2.043 Length, 5/8-24 tpi, 22-30 cal. Small timing collar tapers to fit best on Sendero Lite  and Rem Varmint contours