The bottle and cap are made from BPA-free materials and food-grade steel. It's free of toxins and safe for you to use and drink from. Single layer wall stainless steel water bottle,no heat preservation function, be careful when adding hot water. Specially designed insulated stainless steel cap is leak-proof and has a heavy-duty thread to help it stay firmly attached. The mouth of the bottle is big enough for you to add ice cubes or fruit to your water and drinks. Included is a free hook.