HUXWRX silencers feature a patented Flow-Through design unique in the industry. This design creates channels that move gases throughout the silencer, creating tremendous surface area and drag. The FLOW 556k is DMLS printed in 17-4 Stainless, delivering superior toxic fume mitigation, flash reduction, sound reduction, recoil reduction, accuracy, and repeatability. Full-auto rated and compatible on 5.56, 17 HMR, and 5.7 platforms. Has passed the SOCOM Reliability Stress Test a minimum of 6 times. Compatible with Muzzle Brake-QD 556 and Flash Hider-QD 556. Note: If this product is reflected as in-stock it means it's either physically in-stock or allocated and available (serial number is assigned) at my distributor