The entire product line of OPS INC is designed for the unique requirements of the U.S. Military. One of these requirements is that the units are designed to drain water in the muzzle brake suppressor (MBS) in six seconds or less. Since the MBS units are fusion welded 300 series stainless steel, the devices can be submerged in salt water and sustain abuse that will cause other manufactures suppressors to fail. All of our suppressors are self cleaning and maintenance free, and can be attached and removed without the use of any tools. The patented design of the devices raises the normally low frequency blast sound to a primary ultra high sound pitch. This provides for a very compact unit that has the best attenuation figures of any suppressor on the market. From practical tests and the use of the units in combat for over 20 years, OPS INC suppressors have proven to be the best available, and the choice of the top operators. If you don't see your caliber listed, contact us and we can let you know your options. 5.56/.22 caliber models include muzzle brake kit: muzzle brake, barrel fitting, thread protector, and crush washer. The 12th model 7.62/.30 caliber includes the muzzle brake and thread protector.