FOR Systems Monarch Recce. Compact 5.56/6mm suppressor purpose-built for AR platforms. DMLS 3D-printed Inconel 718 construction. Active Transport mesh structures diffuse high-pressure gases without excessive backpressure. Excellent flash suppression. 4.9" long, 13.6 oz (without mount), 1.625" diameter. .243 cal bore (.275"). 1.375x24 HUB compatible. C-Series Cerakote finish. 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