This reference leak source is a calibration accessory for REED's C-380 refrigerant leak detector (also compatible with the C-383 and R9300), used to verify the detector is sensing correctly before field use. It contains a small sealed quantity of refrigerant gas that emits a controlled, low-level leak so technicians can test detector response and confirm proper operation. The compact housing is built for repeated use as a routine calibration check tool in HVAC/refrigeration service kits.