This is a BRAND NEW LP/Propane Gas Pilot Orfice for a Standing Pilot Gas Furnace/Water Heater. It goes in various models of ALL Brands. It is unique in appearance and can be easily idenified to the picture! The orfice is 1/2" tall and 3/8" wide at the base. These orfices often clog with dirt and reduce the size of the pilot even after cleaning. They should be changed out every couple years. (See our store for the Nat Gas vesion which looks identical but has a difference size opening!) Thanks for looking and good luck!
An orifice / piston is a device with a small hole which allows gas or liquids to flow through at a slow rate. In furnaces, orifices are usually used for regulating pilot and main gas flow. In air conditioning units, orifices regulate the flow of freon.