BAMBOO OUTSIDE, STAINLESS STEEL INSIDE : It looks great and has a distinctly elegant look that makes it different than everyone else's coffee cup,it is also comfortable to hold.Food grade stainless steel inside,you can be to use it safely. RUBBER SEAL RING AND FOAM PAD : As you can see in the picture,we use rubber seal ring try to make your coffee or tea hot for longer and prevent leak,and It 't slide around because of the foam pad when you set it down.But it's not designed to prevent 100% of your spills. If you throw it in a bag or hold it upside down, liquid will come out. EASY TO CARRY AND CLEAN:This fit in a cup holder when you go to work or travel and it is easy to wash by hand,but not dishwasher,after all it is bamboo outside. A GREAT GIFT : It's a great personalized gift idea! Best novelty coffee mugs. Coffee mugs for men and Coffee mugs for women. Drinkware Type:Mugs Type:Coffee Mugs Style:Brief Specification:1 Accessories:With None Shape:With Lid Capacity:450ml/ 15oz Colour:Bamboo color Material:Bamboo + stainless steel Size:6.7*8.3*17.8cm Package Contents: 1* stainless steel bamboo cup Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.