Pair of .010 oversize pistons for 1971 and older 900cc sportsters. You can see part number M17549 in one of the pictures. It's also shows that it's .010 oversize. Selling one pair of Pistons per listing. That's enough to do one engine. Please note that these do not come with the Rings and you have to purchase them separately yourself. Note that this is older inventory and has been sitting in a warehouse for decades.