Replacement for 1964-1966 Ford Mustang models, w/ Factory A/C The receiver/drier helps maintain proper temperatures inside your car by removing contaminants and moisture from the air conditioning system. It's role is very important because moisture is the #1 Enemy of air conditioning systems.  Compatible with both R12 and 134a automotive refrigerants. It is necessary to replace the receiver/drier anytime the system is opened up to the atmosphere. ...