Butterfly valve gaskets are tricky. Really the best way to know is to get the gasket from the same brand and supplier from where you got the valve. We can say these will fit the butterfly valves that come on all MoreBeer! Pro tanks. Otherwise sometimes the best way to figure out which gasket will fit is to order a few different brands and see what works. There are such subtle differences and sometimes you can get a gasket to fit but it may not last as long as having the correct brand.