Fuel Level Sender | Liquid Level Sensor - Fozmula Rochester Sensors is a private limited company, specialising in the design, development and manufacture of a wide range of mechanical sensors and fuel level senders. Founded in 1977, Fozmula is a private limited company, specialising in the design, development and manufacture of a wide range of electro-mechanical, mechanical and electronic sensors and gauges for equipment requiring liquid level, temperature and pressure measurement.