The 5-2-1 Compressor Saver CSRU2 Hard Start Kit is designed for 3.5-4-5 ton AC HVAC condenser units operating at 240V. This unit type is specifically made for HVAC and refrigeration systems, providing a reliable solution to reduce the strain on the compressor during start-up. The brand of this hard start kit is 5-2-1 Compressor Saver, known for its quality products in the HVAC industry. This model, CSRU2, offers a practical and efficient way to improve the performance and longevity of your HVAC system.