Trane FUS1329 Open Fuse Link 218°F 5‑Pack is a pack of five open fuse links designed for HVAC systems. These fuse links act as thermal safety devices: if the ambient temperature or electrical load exceeds the rated 218 °F (104 °C), the fuse element melts and breaks the circuit. https://www.partshnc.com/104c218f-open-fuse-link-5pk-5