Mossberg 500 Mariner in 12 gauge with 18.5-inch barrel. Marinecote stainless finish for corrosion resistance. Designed for marine and coastal use. Type: Shotgun Action: Pump Caliber: 12 Gauge Capacity: 6 Year introduced: 1961, USA Weight: 7.25 oz Overall length: 37.5" Status: Active Intended use: Marine/Coastal Defense