The Starrett No. 270 Taper Gage is a very useful tool, especially for bearing work and for gaging slots. The gage is made of quality tool steel 7/16" (11 mm) wide by 6-1/4" (160mm) long and is accurately tapered throughout its entire length for quick and convenient measuring of slot widths, etc. One side is graduated from .010" to .150 in thousandths of an inch and the reverse side from 0.3 mm to 4 mm in one-twentieth of a mm (0.05 mm).