These protractors tackle large jobs.Both styles include a black easy-grip locking knob, adjustable clear plastic magnifying pointer, non-corrosive hardware, easy to read numbers, a hang hole for storage, and a composite brake material for locking arms in place. The single arm Equalizer™ Protractors come with either a 1/8Ó thick x 9Ó square clear polycarbonate or aluminum plate. The four edges of each plate are graduated; (1) 1/16Ó graduated left-to-right, (1) 1/16Ó graduated right-to-left, (1) 22 1/2 cm graduated left-to-right, (1) 22 cm graduated right-to-left. The degree scale is graduated to 1/2 degree with 1/4 degree readings possible. Various elements of industry find these protractors a much needed necessity to accurately measure/set-up angles, saving time and money in the process. Used by: Engineers, Welders/Fitters, Sheet Metal Fabricators, Tube and Pipe Fabricators, Wood Workers, Drafts Persons, Inspectors, etc.