The VENT Spiritus 5.56i features innovative Purposely Induced Porosity and 3D-printed Inconel for superior strength and heat resistance. Compact at 6.01 inches long and 1.625 inches diameter, weighing only 15.75 oz. Heat-resistant black PVD coating. Comes with 1/2x28 direct thread adapter to 1-3/8x24 (HUB). Supports limited full-auto firing (90-120 rounds in bursts with 10-minute cool-down). Minimum barrel length 10.3 inches for 5.56x45 (no minimum for 5.7x28). 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