We haven't tried, but we're pretty sure this mug could tumble down Everest and still be ready to drink from when you reach the bottom.It's easy to use thanks to a one-handed trigger which seals when you stop sipping. It's also completely leak-proof, so you can throw it in your pack without running the risk of staining all your kit with hot coffee.Vacuum-insulated travel mugKeeps contents hot for up to 6 hoursOne-handed self-sealing trigger with a lock-open buttonSuper-strong leak-proof cap - withstands impactFits in most cup holdersDishwasher safeBPA, BPF and BPS freeMaterial: stainless steelWeight: 205gCapacity: 350ml | 11.8fl oz