The Hastings side wall is rolled over 7/8" O.D. steel pipe to enhance strength, rigidity, and life. The smooth surface and water drain plug make this tank easy to clean. The 4-Ply bottom seal locks side wall to bottom and makes the unit strong and durable. Tanks are available in either 20 Ga. or 22 Ga. Galvanized steel. Material is measured in accordance with AISI standards (20 Gauge is .036 min. and 22 gauge is .030 min.) The 22 Ga. Round End tanks are available with one or two poly drinkers.