Well, actually it is a very well made plastic tube. They are marketed to carry fountain pen ink for travel but are air and water tight and weigh nothing in the pocket. You can easily tap out your snuff onto the back of your hand or a boxcar. They even come with labels and you can get 10 of them for $2.95 (US). The threads are on the outside so that they don't get clogged with snuff. These work perfect for me and allow me to bring along as many different snuffs as I want to through the day. Easy to fill with a snuff spoon and easy to clean out. Just thought I would share this with those that are frustrated by smashbox spillage and want a more portable and airtight solution to a traditional snuff box.
What I do is still bring my main snuff in a plastic snuff box and then those I am sampling/trying in these tubes.