The Fermenator 42 Gallon Extension is an add on unit to the 27 gallon Fermenator. When you combine the two units you end up with a combined total capacity of 42 gallons. Perfect for those brewers who like to make large batches, or for a nano-brewery. Fermenator will ship directly from the manufacturer. Please allow a few extra days for delivery. Note: The extension will only work on the 27 gallon Fermenator.