The Mossberg 500 Mariner with 20-inch barrel and Marinecote nickel finish. Adds one round of capacity over the 18.5-inch model. Full corrosion resistance for marine environments. Synthetic stock and bead sight. Type: Pump Shotgun Action: Pump-Action Caliber: 12 Gauge Capacity: 6 Year introduced: 1987, USA Weight: 6.75 oz Overall length: 40" Status: Active Intended use: Home Defense, Marine, Tactical