These chew proof glass bottles are ideal for Hamsters, Rats, Guinea Pigs, Rabbits and other small animals. Also excellent for small to medium size birds. They come with a steel cap, metal mounting spring with clips and a rubber stopper with stainless steel tube and control balls. This rubber stopper offers superior performance for less water dripping and the chew proof cap is excellent for preventing chewing of small pets. This bottle can be mounted inside or outside of the habitat. Also comes with extra support wire and floating water indicator. Available in 2 sizes: 6 oz., 12 oz.