Tim, the tube is black (so as not to mix it up with my white one used to protect the fresh fruit that I sometimes will carry as a treat after the first day). It is 4" in diameter. I have one that is 12" in length and another that is 18" in length, (more capacity...longer...trips) and you follow this procedure: (remember, you asked) 1) Pick a place to do your dooty. 2) Do your dooty. 3) Take our your dooty baggie. 4) Use your dooty shovel to scoop your dooty into your dooty baggie. 5) Close up your dooty baggie. 6) Deposit your full dooty baggie into your dooty tubie and close it up. 7) Clean/put away your dooty shovel. 8) Repeat as needed. This really is a gross topic, but it keeps my crap out of the alpine wilderness.