You should pay attention to the material from which the thermocup or thermos is made. Choose high-quality, eco-friendly and safe for health materials. You should check the mechanism for closing the thermos, it must be reliable and not leak. Between a thermocup and a thermos flask I would choose a thermos flask. It is more convenient, you can keep food in it. There are many reviews of thermos flasks on this portal
bestvacuumflask.com. You can choose the product you need. I have Stanley Adventure Vacuum Crock, It's perfect for hiking.