A compost tumbler is usually some sort of a barrel with a door and ventilation holes. Composting
ingredients
are added, and the barrel tumbled to mix.
Tumblers turn on a short or long axis. Or, some gardeners create the tumbler and kick it around to mix the compost. It doesn't matter, either way, it gets the job done.
There are a vast array of commercial compost bins and tumblers available. Some are quite pricey. It's not that hard to build your own compost tumbler.
Click below for a video on how to build one. The family lives in Puerto Rico, I believe, and the scenery is awesome. Watch for their special "compost activator".
How to Build a Tumbler for Compost
Here is another video for building a tumbler. This one turns on a short, horizontal axis.
Tumblers versus Bins
Tumblers are great because they do two jobs at once. But don't discount bins either. A simple box bin is easy to build and easy to work with. Be sure to make one side open completely for easy access.
Two bins side by side can make turning easier. When ready to turn, turn the compost into the adjacent, empty box. Or, create a box with no bottom and lift off when it's time to turn. Place the empty box adjacent to the pile and turn back into the box. Tumblers Advantages:
combine containing and turning in one unit
save space as compared to a pile
Disadvantages:
may need added space to operate
more difficult to remove finished compost
Bins Advantages:
may use less space than a tumbler
no additional space needed to turn
can be easier to remove compost
usually easier to build
Disadvantages:
more space needed if using multiple bins for turning
more labor to turn
This video gives a nice, short summary of bins versus tumblers: