Compressed air systems use a wide variety of valve types. Compressors often use an unloader valve (solenoid valve) to ease the starting of the pump. In the generation of compressed air condensate is created. This has to be drained adequately in order to increase the life of the system. There are different automatic condensate drain systems available, including electronic time-controlled solenoid valves and fully mechanical drains. Leakage of compressed air is an unwanted expense. To avoid losses outside working hours, an electric ball valve is often installed behind the compressor. All valves and components for controlling compressed air for air-driven equipment, are provided in the category pneumatics.