The Trane GLS0077 Sight Glass is an HVAC refrigeration component designed to provide a clear visual view of refrigerant flow within a system. Installed in the refrigerant circuit of compatible Trane air-conditioning and refrigeration equipment, it allows technicians to observe flow conditions and identify abnormalities such as bubbles or insufficient refrigerant movement. By providing... https://www.partshnc.com/trane-gls0077-sight-glass