LEAK-PROOF. LIKE, REALLY LEAK-PROOF. The Aladdin Stainless Steel Vacuum Insulated Mug features our new intuitive Flip-Seal leak-proof lid - flip back to sip, flip forward to seal (it's really that simple). The perfect everyday on-the-go coffee or tea travel mug is car-cup holder friendly, dishwasher safe and BPA free. Plus, the stainless steel body is vacuum insulated to keep drinks hot for 3hrs or cold for 20hrs. No matter where you're going, just throw your leak-proof travel mug in your bag and when you get there your things will be dry and your drink will be just the way you like it.