Contigo AUTOSEALu00ae technology guarantees 100% spill and leakpoof drinking experience by sealing automatically between sips:press gently to drink and release to seal. The Metra drinking mugsuse vacuum-insulated technology, keeping hot drinks hot for up to 5hours and cold beverages cool for up to 12 hours. The lid flexesopen for easy cleaning and there are no loose parts. Twist the lidto automatically lock the Autoseal button and cover the drinkingspout from dirt.