The M4SD II sound suppressor is the result of a ten year study of sound suppressor design and rigorous seven year R&D program pulling from lessons learned in environments from computer design, field testing, to actual combat operations. The M4SD II was designed to provide the end user with an extremely durable, high performance, and versatile silencer for semi auto 5.56 carbines. The optimal combination of lightweight, peak performance, durability and flexibility was accomplished in the M4SD II. The M4SD II is CNC machined, and TIG fusion welded for maximum thermal transfer and unparalleled strength and durability. Every component in the M4SD II is manufactured from high strength, high temp, corrosion resistant 17-4ph Stainless Steel. The M4SD II has the best balance of muzzle and ejection port sound signature on the market today. (according to internal MIL-STD sound testing with current competing products in class). Unique to Griffin M4SD family suppressors is it's SDQD mounting interface. The mounting system is one of the fastest on the market and accommodates the A2 nato compensator as well as Griffin's proprietary performance rich muzzle device options. Additionally the M4SD mounting system does not suffer from the wear prone issues of ratcheting systems common to the marketplace. Our mounting system was designed to provide trouble free use. The mounts of the M4SD II sound suppressor are precision ground to ten thousandths of an inch for minimal, repeatable and completely dependable point of impact shift. Built on a mountain of development, the M4SD-II is the pinnacle of performance- the equal of the best competing products available anywhere in the world.