Digital Protractors to measure inclination values on an easy-to-read LCD. Measurements are generated by an electronic gravity sensor. Full 360? range (90? x 4). Alternate reference (zero), Reading hold. Display remains upright to view at all angles. (950-317, Pro 360 Model). Accuracy: ?0.1deg Level ?10 deg, Plumb ?10 deg, ?0.2 deg Maximum error, Repeatability: ?0.1 deg and Resolution: 0.1 deg