Fowler 52-243-212-1, 2" - 12" Inside Micrometer

2 - 12 Inside Micrometer Fowler extension rod type Inside Micrometers have a wide measuring range-any one single micrometer can replace many bar type inside micrometers. Includes: case wrench reference standard Features: Each set consists of an inside micrometer head and a series of fully hardened and lapped extension rods of different lengths all with carbide measuring faces Anvil and spindle are hardened and precision ground with microlap finish on ends. Spindle thread hardened, ground x (3 + L /2) Meets or exceeds Federal accuracy specs. Reference standard included with set.