Details: Starrett Micrometer Part # 50754 T221XL No. 221 Hi-Precision Micrometer permits direct readings in ten-thousandths of an inch (.0001") without a vernier, plus automatic control of spindle pressure. This micrometer features a black graduated inner thimble and sleeve reading in thousandths and a red graduated outer thimble and sleeve with large, widely spaced graduations which give direct readings in ten-thousandths. It also features an exclusive constant pressure mechanism which eliminates "feel" and automatically insures consistent spindle pressure for every measurement. Extremely easy to use. Headquartered in Athol, MA, in the heart of New England, where manufacturing began and evolved into what it is today, Starrett has a history and reputation so rich and solid that the words quality and Starrett are virtually synonymous. The broad Starrett product line includes precision tools micrometers, calipers, rules, tape measures, levels, electronic gages, dial indicators, gage blocks, granite surface plates, optical measuring projectors, vision systems, vises, M1 lubricant, and precision ground flat stock. Much of the Companys production is concentrated in hand measuring tools and precision instruments that many manufacturing companies, from small machine shops to Fortune 500 firms, buy for the use of their employees.