I just bought two of these (Indian pumps) for our upcoming jet meet this year from a company called Ben Meadows. They have the poly (plastic) type and are less expensive, if I remember correctly, than the metal type.

A quick search for Indian extinguishers will find Ben Meadows. They had the best price I could find and are available in both 4 & 5 gallon containers. There is also an additive you can buy from Forestry products that is suppose to dramatically increases the ability to extinguish the fire faster.

Gary