The Nissens A/C Compressor Kit - 451726 is a comprehensive kit of products designed for use in a car's air conditioning system. It includes six different components, each serving a specific function in maintaining and repairing the A/C system. The kit contains a compressor, which is responsible for compressing and circulating the refrigerant in the A/C system. It also includes a condenser, which helps to cool down the hot refrigerant gas and turn it back into a liquid. The kit also contains an expansion valve, which regulates the flow of refrigerant into the evaporator. The evaporator, which is also included in the kit, is responsible for cooling down the air that is blown into the car's cabin. Additionally, the kit contains a receiver-drier, which serves as a filter and moisture remover for the refrigerant. Lastly, the kit includes an o-ring seal, which helps to prevent leaks in the A/C system. This Nissens A/C Compressor Kit - 451726 is a comprehensive solution for maintaining and repairing a car's A/C system, ensuring that it operates efficiently and effectively.