CoZroom 20oz Stainless Steel Tumbler Regular Lid with Stainless Steel Drinking Straw for Hiking Travels Camping The vacuum tumbler with high quality material which will prevent heat transfer to the outer wall of the tumbler. The tumbler has been designed to keep you drink ice cold up to 24 hours and keep your warm drinks hot up to 6 hours. Tumbler cups with a sweat free design to prevent any condensation on the outside of the cup so it will not be slippery while holding it and you will never burn yourself again. The highest quality of stainless steel is chosen to make vacuum cup which is non- toxic, BPA free and is against rusting and leaching. With the vacuum tumbler the pack included a BPA free stainless steel drinking straw to able to drink in totally safety and never spill a drink on yourself. And it is eco-friendly and easy to wash.