Not necessarily. Baby feeding systems often include a bottle warmer, bottles, and sometimes a breast pump that all work together. While it can be nice to have a bottle warmer than perfectly fits the bottle, it usually isn’t necessary. If your baby has one type of bottle he loves, by all means, get the warmer that goes with it. Otherwise, a bottle warmer with a universal warming chamber works well, because your child may prefer a different type of bottle later on … or you may have another child who likes a different bottle style.