Permanent below deck fuel tanks tested to retain pressure and withstand motion.Light, strong and tested tough, these aluminum tanks are the choice of many boat manufacturers. Built to meet the rigorous standards of the US Coast Guard as well as the NMMA. RDS fuel tanks are built of 5052 aluminum alloy and tested for their ability to retain pressure and withstand motion, impact and fire. Before welding, all aluminum parts are bathed in acid to eliminate any contamination that might weaken a weld or create the potential for leakage.Key featuresSide corners are radius bent, not weldedAll Tanks-have 1/4" NPT pickup, 1 1/2" fill, and 1/2" vent fittingsAdd 3" to height for fittingsAll are fitted with plugs for diesel returnAbove-Deck Tanks have vented caps with gauge unitsBelow-Deck Tanks have electrical sending units & removable vent plugsSpecificationsMaterial: Aluminum Capacity: 18 GallonDimensions: 24 1/2"L x 16 3/8"W x 10 3/8"HFitting Type: 1/4" pickup, 1 1/2" fill, 5/8" vent, 3/8" return for dieselGauge: Electrical sending unit included Securing System: Brackets included