PolyJohn Enterprises holding tanks are designed to be used in tandem with job site trailers. The tanks are sanitary receptacles used for collecting waste in portable restrooms. They can be a necessity for long-term portable sites where indoor plumbing is not an option. Made from durable plastic, the holding tank design is functional and discreet. It’s also compatible with other PolyJohn restrooms and sinks, and can be easily configured with most any type of plumbing. They are available in 250- and 300-gallon capacities. 800/292-1305; www.polyjohn.com.