I am selling the two different 5 gallon brewers from Keep it Simple, pioneers in the compost tea industry.
I started using their compost tea brewer in 2005, since they were (and still are) highly regarded in the world of compost tea and endorsed by Elaine Ingham of the Soil Food Web.
All of the information about these brewers - and the differences between the two - can be found on their website at www.simplici-tea.com. Note that my prices are a bit higher because of customs.
The basic 5 gallon brewer is the one I started with. It is powerful! It is the only brewer I know of that produces a tea that is very high in microbial numbers and biodiversity in only 12 hours. It will last for many years of home garden usage.
The 5 gallon extended life brewer pushes a little less air, so it takes at least 24 hours to produce a good tea, but it is a bit quieter and the motor lasts much longer.
The higher price is worth it for those who know they will be brewing fairly often over many years and who don't mind the longer brew time.