Ten (10) custom handmade leather pump cup washers. Replacement part 216-5091. The cup diameter is approximately 7/8" (also referred to as the 21mm size). These are handmade by me from high quality vegetable tanned leather -- vegetable tanned leather is safe for use with the metal in your stove/lantern. (Non-vegetable tanning processes have chrome alum/chromium salts in the leather which corrode metal over time). These leather cups are a perfect fit. Leather washers can be installed in just a few minutes with just common everyday household tools/items. Get rid of the neoprene washers! Upgrade to leather.