Camco Propane Gauge/Leak Detector, Type 1 Connection for Gas Grills, RVs and Boats Type 1 connection for gas grills, RVs and boats Fits a DOT propane cylinder manufactured after 1995 that have the ACME/OPD connection See at a glance when your propane pressure level is low Provides excess flow protection in case of a broken gas line and thermal protection in case of fire Will not read levels immediately: begins working when propane is flowing