If your scupper is fine, why replace the whole thing? This flapper kit has a 1-11/16" diameter black rubber flapper and stainless steel retainer wedge and machine screw. Fits any scupper with a 1-11/16" flapper.
If you have another scupper, just measure the flapper and: If it is 2" in diameter, you need Scupper Flapper Kit PER0002.
If it is 1-3/4" in diameter, you need Scupper Flapper Kit PRE56555FLAP.
If it is 1-5/8" in diameter, you need Scupper Flapper Kit PRE56677FLAP.