Stanley One Hand Vacuum Mug 8 Hour. A winter touring marvel, a commuter's best friend, the city biker's right hand man, the Stanley One Hand Vacuum Mug is a marvel of thermal drink warming technology. Its 188 stainless steel construction is BPA free, and corrosion proof and abuse proof. The seal is so good on this mug that you could drop it into a pannier or pack and it will be there for you when you get to point B piping hot. In fact, if you were willing to be parted from your precious coffee, you could leave it for 8 hours and it'll still be hot.