- Non-Typical 55 Gal. Poly-Lower Unit fits 55 gallon barrels, both metal and plastic- 6" down spout- Weather, rust, and leak proof- Maintenance free unit will provide years of trouble free use- Built to be outside 24-7, 365 days- Extra deep funnel design adds feed capacity to your 55 gallon drum- 22 3/8" O.D. (Outside Diameter) on the funnel- Funnel without gravity head is 18 1/2” deep