Marshall Excelsior Propane Adapter Tee Model ME412P. The ME412P camping appliance tee allows the RV owner the ability to connect either one or two high pressure LP gas appliances from a single LP gas cylinder source. The Marshall Excelsior ME412P features two male 1in 20 high pressure propane connection ports for powering portable camping appliances such as: camp stoves, lanterns, table top grills, portable heaters, and other small LP appliances. Tee adapter, QCC1 x Male 1in 20 x Male 1in 20, packaged.