Build your own rainwater catchment reservoir with this 16" strainer and with a bulkhead fitting, quickly set-up your own rainwater irrigation system. Unlike our 5 gallon version that fits on almost all 5 gallon buckets, these fit some, but not all 55 gallon drums. If the opening on your barrel has a hole on the top bigger than 16"  you'll need to either cut a circle for it in the top you have, or in something else that will cover the rest of the reservoir's top -- and you can use these same methods with for almost any size reservoir.