The high quality metal drinking spout and cap unit ensures these bottles are chew proof and Classic's industry famous double ball bearing method of water retention / release guarantees a leak free bottle. Fun Carrot style water level indicator allows you to see at a glance whether it needs refilling and a capacity graduation on the bottle back is useful for specific filling level requirements. The bottle attaches to your pet's cage at two separate points through a sturdy spring clip and hook bracket. Manufactured from recyclable glass, this bottle is dishwasher safe in the top basket.