This is a SPI 10-710-2 Hole Micrometer Set with a range of .275 inches to .500 inches and 3-point carbide anvils. It is made in India and designed for mechanical reading with a resolution of 0.00010 inches. The micrometer type is a bore micrometer suitable for metalworking inspection and measurement. The brand is SPI and it falls under the categories of micrometers, metalworking inspection & measurement, CNC, metalworking & manufacturing, and business & industrial.