Even on the hottest days, the water-cooled Isotherm SP operates consistently at a high level of efficiency. The SP thru-hull is a patented device which can replace your galley sink drain without making new holes in the hull. The SP fitting is approximately 2.5 inches (60 mm) in diameter. Each SP Refrigeration System comes complete with pre-charged compressor, evaporator, thru-hull, mounting bracket, thermostat, and shut-off valve (sea cock) for the thru-hull fitting. The SP system works without fans or water pumps to remove the heat generated by the compressor. The SP system consumes less battery power than a conventional seawater pump or fan cooled system and is remarkably quiet. Each system features quick connects for easy installation with 9 feet (3 meters) of refrigerant line between the evaporator and thru-hull, six feet (2 meters) between the compressor and evaporator, and three feet (1 meter) between the compressor and thru-hull. Prolong Extension Tubes which come in pre-charged pairs with quick-connects can be inserted in the loop at any point to extend the length between components by one, two, or three meters.