This item is designed to be inserted into a plastic bottle. By swapping the included straws of different lengths, it can be used with both 500ml and 350ml plastic bottles. It cannot be used with carbonated drinks or hot beverages (use below 25°C). There is a possibility of leakage when squeezed, tipped over, or carried, so storing it upright is recommended for safety. It is not dishwasher or dryer safe. It can be washed by hand and reused. Photos 9-11 show actual usage examples. Pressing the white part of the lid will pop it open, and the straw will appear. You don't need to hook your fingertip to open the lid. To close it, press the lid with your fingertip. Use it while walking, in the car, watching TV, or reading – feel free! I tried one, and it was surprisingly convenient. It's new and unused, but please consider it if you don't mind it being stored at home for a long time. Thank you.