The Starrett 824M series fixed range vernier inside micrometer has an adjustable sleeve and adjustable contacts on the thimble end help provide accurate measurements, and a vernier scale in inch units for making precise measurements. A knurled thimble helps provide secure grip, and the handles are heat-insulated to help reduce temperature-related expansion or contraction. The vernier scale is graduated to 0.001” and a knurled ring-type lock nut holds measurements in place. The micrometer has a satin chrome rust- and glare-resistant finish.Micrometers are precision measuring instruments that use a calibrated screw to measure small distances. These measurements are translated into large rotations of the screw that are then able to be read from a scale or a dial. Micrometers are typically used in manufacturing, machining, and mechanical engineering. There are three types of micrometer: outside, inside, and depth. Outside micrometers may also be called micrometer calipers, and are used to measure the length, width, or outside diameter of an object. Inside micrometers are typically used to measure interior diameter, as in a hole. Depth micrometers measure the height, or depth, of any shape that has a step, groove, or slot.The L.S. Starrett Company manufactures precision measuring tools, metrology and testing equipment, and saw blade products. The company was founded in 1880 and is headquartered in Athol, MA.