Avex- Matte Black 20oz Highland Insulated Travel Mug
We use these travel mugs. The Highland Insulated Travel Mug is super-insulated and keeps coffee hot for hours. The lids are really bomb proof, do not leak and the valves work great.
Here's what Avex says about the mugs:
The Avex Highland Insulated travel mug keeps beverages hot for up to 7 hours and cold for up to 20 hours. It is 100% spill/leak proof. It's vacuum insulation maintains temperature and it's double-wall exterior eliminates condensation. Dishwasher safe.