True Blue vials are accurate to within 0.0005 In. (inch) per inch in all working positions. Heavy-duty extruded aluminum frame. Vials read plumb, level, and 45 degrees. Strong hold magnetic edge. V-grooved working edge fits on pipe or conduit. No. EM81.9: Length: 9 In., Material: Aluminum, Magnetic: Yes, Number of Vials: 3, Pkg Qty: 1, Package Type: Card