Questions & Answers about Si esa no me queda bien, me probaré la otra.
Because Spanish often leaves out the noun when it is already understood from the context.
Here, esa means that one and la otra means the other one. The missing noun is feminine singular, probably something like camisa, chaqueta, falda, etc.
So the full idea is something like:
But Spanish normally avoids repeating the noun if it is obvious.