The Bell & Gossett 118705 Coupler Coupling is a 1/2" x 1/2" fitting designed specifically for the Series 100 model in HVAC and refrigeration systems. Made in the United States, this high-quality coupling is a reliable and durable component that ensures smooth and efficient operation of the system. With a straightforward design and no modifications needed for installation, this coupler coupling is a convenient and essential part for maintaining and repairing HVAC systems.