If your scupper is fine, why replace the whole thing? This flapper kit has a 1-5/8" diameter black rubber flapper and stainless steel retainer wedge to fit any scupper that has a 1-5/8" 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 1-7/16" in diameter, you need Scupper Flapper Kit PRE56553FLAP.