Designed specifically for the 308 and 7.62 mm caliber cartridge the 14 x 1 L Eclipse Flash Hider uses a slightly twisted triple prong design to reduce flash to near zero in even total darkness conditions. The device is threaded 14 x 1 L metric and will clear any projectile up to 311 caliber and 7.62 mm. Do not use with larger calibers. The Eclipse Flash Hider is marked “MA” and “30” and a crush washer is included. Use the crush washer instead of the detent pin for installation (detent pin may be left in place)