I'm doing some remodel in one of my bathrooms. I have the wall out and can see the bathtub in my other bathroom. I noticed it was leaking around the drain and wanted to replace the seals on it. It's an older fiberglass tub/shower and I was curious whether most of the kits are a standard size or if they're all different. I suspect they are standard but i thought i would ask before i went and spent any money.