The Self-Contained Slide-In Unit from Imperial Industries is offered in two designs: single compartment for grease or industrial sludge and two compartment for the portable restroom industry. It includes a horizontal freshwater tube and extruded skid design. Stock units are manufactured in steel, aluminum or stainless steel with capacities of 300, 450, 550 and 650 gallons. They are equipped with Masport or Conde vacuum pump packages, featuring Honda gas engines. 800/558-2945; www.imperialind.com.