Each Flange set includes one Flange Base and one 25mm Flange cup. If you have single-piece Flanges, this Flange set will replace one of those and will work with all of your other parts except flat gaskets. If you have flat gaskets, you must replace them with O-Rings (part 735) to adapt this new Flange to your older Nurture III parts. If you need a larger Flange, try the Super Shields (part 765) inserted into your Flange set. For double pumping, order two Flange sets.