DC-900650-1.5, Duracast 650 Gallon Plastic Storage Tank | 900650 These vertical storage tanks are rotationally molded to eliminate the need for seams or joints. The one-piece structure of these tanks improves durability and decreases the chance for leaks. These tanks can be used both indoors and outdoors. The polyethylene resin is compounded with UV stabilizers to provide the tanks protection from harsh UV rays. People can use these vertical storage tanks to hold a variety of contents, ranging from industrial chemicals to liquid fertilizers. Designed to be low-maintenance, these storage tanks are easy to clean and will not rust. The gallon calibrations molded into these tanks allow you to calculate content levels quickly and let you know when tanks need to be filled. This is a 1.5 specific gravity tank.