The most popular precision micrometers used by skilled workmen worldwide  Accurate, rugged, and easy to use  Protective case keeps micrometers and standards together, readily accessible  Hard and stable one-piece friction thimble permits one-hand operation of micrometer and uniform contact pressure  Balanced frame and thimble design ensure easy handling  Micro-lapped measuring faces  Starrett No-glare satin chrome finish on thimble and sleeve minimizes annoying surface glare under bright lights and resists rust  Anvils sized at .250" (6.35mm) diameter.Includes:13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 & 24 in 436 Series Micrometers(12) Standards