If you own the AARKE carbonator it comes with ONE PET bottle for carbonation. Most people enjoy having 2-3 bottles total depending on their daily water consumption. This bottle is the same as the bottle that comes with the machine. PET bottles are NOT dishwasher safe. Please only wash by hand with cold or warm water. Do not carbonate anything other then WATER. Each PET bottle has an expiration date on it. The date should be minimally be 2 years out. Please exchange your bottle after the expiration date..