Safety Design for safety and health drink, made entirely of food-grade silicone material, same to the material of baby pacifier; free of BPA, BPS, phthalates and other harmful chemicals. Durable Sturdy and durable enough to withstand extremely high-strength squeezing, 100% guarantee for your drinking needs. Leak Proof preventing leakage and overflow with patented high-strength alloy sealing screw cap, ensures that the round cup mouth is not deformed even under the extrusion environment Portable Collapsible design for saving your traveling backpack space, with only 50% of the space when fully folded. Holds 17oz of water when fully expanded. Multiple Scene Suitable for outdoor activities such as Travel, Hiking, Camping, Gym, Biking, Running, Fishing, Climbing, Picnic and Beach Note: 1.After opening the cap, it can be stretched and folded. 2.When using for the first time, it is recommended to soak in boiling water for 20 minutes for thorough cleaning. 3.The suitable temperature range of the water cup: -76F (-60C) to 446F (230C). However, we do not recommend using it in liquids with a temperature higher than 140F (60C) to avoid scalding your hands.