MODEL #LINKMANUAL D400 - Refrigerant Gas Leak Detector D440A - Refrigerant Gas Leak Detector D440A-UV - Dual Mode Refrigerant Gas Leak Detector D540 - Combustible Gas Leak Detector D640 - Nitrogen / Hydrogen Tracer Gas Leak Detector D740 - H2 Tracer Gas Leak Detector D740KIT - Tracer Gas (H2/ N2) A/C System Dealership Leak Detection Service Kit