Stainless Steel Non-Tip 530mL/18 oz travel tumbler with Smartgrip Technology: this mug takes hold on any flat surface, like tables, desk or counter tops, and will not knock over if bumped into. Double walled vacuum-insulated stainless steel to keep beverages warm for 6 hours and cold for 12 hours. Vacuum-sealed, spill-free. Car cup holder friendly. Ideal for travel and car trips. Dishwasher safe.