Features: 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 assured 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 won'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.