The Griffin Tactical MK1 PSD Lightweight Upper was designed with weight savings in mind, while still providing the rigidity you need to maximize your M-LOK setup. These MSR Rails by Griffin Tactical are ultra light yet durable, and the concave M-LOK surface allows you to easily install IR laser aimers or other night time optics for a more precise aiming experience. During the manufacturing of the Griffin Thunder MK1 Upper, the barrel was 3D scanned and CAD designed to provide the most accurate and reliable auto-enhancement platform a shooter can use while running the weapon unsuppressed or suppressed. When the Griffin Thunder MK1 Carbine Upper is in the works, it has all the quality of steel and heat treating that you've come to expect from Griffin Tactical, while the 416R stainless steel and RSM-threads keep this upper functioning well after multiple years of use. Purchase the Griffin Tactical MK1 Lightweight Rail for your ideal aiming experience. Specifications for Griffin Armament MK1 PSD 300BLK 9.5 inch Upper: Manufacturer: Griffin Armament Caliber: .300 AAC Blackout Barrel Length: 9.5 in Muzzle Device: Griffin Silencer Mount Muzzle Device Finish: Anodized Color: Black Model: PSD Gun Rail: M-LOK Condition: New Magazine Included: No Length: 9.5 in Package Contents: Griffin Armament MK1 PSD 300BLK 9.5 inch Upper