This replacement filler cap has a 2"-10 UNS thread to fit our original Easy-Clean Oil Tanks (prior to 2010*). Measures 2 3/8" OD x 5/8" high overall. This size was used on several different brands of oil tanks made in England from the 1960s through the 80s. Sold individually.
* Our Easy-Clean tanks can be told apart from our newer tanks by the location of the outlet port. The original tanks had the port located within an inch of the bottom of the tank. Later tanks (which take a different cap) had the port several inches higher.