Our silicone sleeves are made out of 100% food-grade FDA-approved silicone. They are BPA-free, non-leaching and non-toxic. Silicone is made of silica, the most abundant compound in our earth's crust. Silica is a naturally occurring element and can be found everywhere from rocks and plants to the insides of our bodies. Our silicone sleeve protects your Kablo glass water bottle against bumps and scratches and provides a gripping surface so you can transport your beverage with peace of mind. We have intentionally designed the sleeve to cover half of the 32 oz bottle to let you monitor your daily intake.