 A special piston-type flushometer, called the Naval, was built for marine applications.In 1976, Sloan introduced the Optima line of sensor-activated flushometers (the first few were installed at Chicago's O'Hare International Airport); battery-powered equivalents under the name Optima Plus followed in 1991.Sloan also now has solar-powered models with a battery back-up that operate using any artificial or natural light source.