Starrett, 67121, 1 Inch, 2-1/16" Plain Thimble, 5/16" Dia x 1-7/16" Long Spindle, Mechanical Micrometer Head 5-1/8" Long, Accurate Up to 0.0001", Rotating Flat Spindle, 1" Dia x 0.56" Long Stem, Carbide Measuring Face