Cheeki's insulated bottles are first constructed with an inner and outer layer. Sealed together they are welded to be completely airtight with a high-power vacuum pump - this removes all the air between the inner and outer layer preventing the transfer of hot and cold temperatures. So no matter how cold or how hot the liquid inside is, it will not transfer to your hand!
Vacuum insulated bottles are totally safe for boiling water and will keep hot for up to 12 hours. If you do put boiling water into the insulated bottles please be careful! The insulating function is highly effective the water will still be extremely hot hours later.