The Boroux SLEEVE is the first option of its kind that combines the strength of insulated double wall Stainless Steel and the crisp and clean taste of ultra clear, thermal shock resistant Borosilicate glass. The SLEEVE comes with a Borosilicate Boroux Original 16.9 oz glass water bottle that is secured within the Stainless Steel Double Walled Insulated `shell. The SLEEVE turns your glass water bottle into an insulated thermos water bottle. The SLEEVE is perfectly used as a coffee thermos/tumbler or water bottle.