This is a BRAND NEW Natural Gas Pilot Orifice for a Standing Pilot Gas Furnace.  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 orifices 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 LP vesion, which looks identical, but has a difference size opening!)  Thanks for looking and good luck!!