MyLifeUNIT Portable Borosilicate Glass Water Bottle with Nylon Sleeve (12.2 oz) The bottle is made of ultra clear borosilicate glass. It's a kind of environmental and healthy material. The cap is made of 304 stainless steel and food grade silicone O-ring . Odor free and safe to drink. The body is made of high quality heat-resistant borosilicate glass and is not easy to burst due to the high or low temperature. The nylon outer cover provides a comfortable feeling and against hot. It makes easier to grip against falling off and effective protect glass body from damage. It's easy to carry everywhere with you whenever outdoor or sporting. The glass is super smooth and transparent, it's easy to wash.