Application: Car air conditioning system. Description: Prevents compressor overload caused by abnormal high/low pressure of refrigerant. Features: Pressure range : 0 ~ 36 Â/Â Diff. High Pressure (6 Â/Â ), Low Pressure(MAX 0.25 Â/Â ) Dual switch type that responds to both high and low pressures. Excellent corrosion resistance and lightweight due to aluminum housing. Refrigerant used : R - 134a, R-12.