Magnetic base features fine adjustment. Base dimensions: 2" x 2-11/32" x 1-13/16". Also mounts test indicators with 1/4" post. Indicator has a range of 0-1" with graduation of .001". Meets AGD specifications Magnetic base also features 85 lb. pull, on-off lever release magnet and V-base for placing on round surfaces. indicator has a continuous reading of 0-100 with a revolution counter and tolerance indicators.