Range: 360° (4 x 90°) Resolution: 0.05°; Repeatability: 0.1°; Accuracy: +/-0.2° Magnets on bottom and two side walls Outside dimensions: 2.2" x 2.2" x 1.2" The SPI 11-983-4 digital mini protractor provides reliable 360° readings (4 x 90°). Magnets on the bottom and two side walls allow the user to position the protractor on ferrous surfaces. Auto shut-off after 3 to 5 minutes conserves battery. Requires one 9 Volt battery (included). Dimensions are 2.2" x 2.2" x 1.2"