A: Hello, Thank you for contacting Danco. The 89042, Danco 5in flat Suction Sink Stopper in White, is made of corrosion-resistant durable rubber. Thank you for choosing Danco. Regards, Product Support
A: Thank you for contacting Danco. We do not recommend this sink stopper if the bottom of your sink is not flat.
A: It may work but I would not recommend for a drain that isn't flat. Perhaps the regular rubber stopper type that actually fits into the drain hole might be better.
A: I’m not sure.
A: Probably not. Flat or a gentle uniform curve.
A: I would depend on the extent to which the bottom of the sink does not lie in a single plane.
A: As long as there is space enough that the curvature of the tub wall doesn't interfere with the seal, then yes, it will work with a tub.