Freon pressure gauge are used in refrigeration systems for testing. Oour dial features R-12, R-22 and R-502 or R-304 scale. Suitable for use on all freon service application, for example: refrigeration,refrigerant recovery and recycling,etc. Filled with damping liquid inside,the stainless stee freon prare suitabe for locations where the working environment shock largely. www.allgakind-instrument.com