Kapro 150-81-24 I-Beam Level with Plumb Site, 24-Inch I-beam spirit level for determining horizontal and vertical plane as well as incline Injection-molded acrylic vials one level, one plumb, and one 45 inclineresist breakage and have a sensitivity of 0.001"/inch Level vial and dual-view plumb vial can be read from the side and the top V-shaped groove in the base provides reliable seating when leveling round items Aluminum body for light weight and corrosion resistance