Bo-Bottle is unique. It is the first glass drinking bottle with a screw-off base. All the glass bottles are made from scratch-resistant borosilicate glass, making them extremely durable. The bottles can withstand a great deal, have a very long lifespan and retain their good looks. The cap and base are made from durable stainless steel. In addition, the interior is made from a non-toxic, hard plastic that is highly resistant to bacterial growth.