The dryer absorbs dirt and moisture to keep the coolant in the air conditioner system clean. It ensures that only liquid is conducted on to the expansion valve. In this way, you avoid destroying the compressor which drives the system, and the A/ will function better and for a longer time without repairs. The dryer is placed either on the condenser near the outlet connection or just after the condenser. The dryer should always be changed together with the condenser. Nissens' dryer is a quality product ensuring long durability for the Air Conditioning system.