This circular slide rule dial calculator helps engineers and technicians determine water flow in pipes and ducts with circular cross sections from 0.5 to 240 in., as well as open-channel areas ranging from 0.7 to 2,000 sq ft, the company says. Constructed of multicolor, engraved solid acrylic, the instrument measures
7 5/8 in. dia and comes with a carrying case and instruction booklet.