Brunson scales have optical targets evenly spaced every 2 mm. The optical micrometer on an instrument works like a vernier, displacing the line of sight laterally. Using this displacement, the reticle is “brought into register” with the nearest target on the scale, and the precise displacement is read directly from the graduated micrometer drum. By adding or subtracting the micrometer’s reading from the scale position, a precise measurement is made. 
 

More information is also available on Brunson's website regarding the patterns, features, and targeting characteristics that are used.
 

All of our metric scales except the 1000 mm size are graduated throughout their stated length. The 1000 mm scales are blank over the lower 495 mm and are graduated over the upper 521 mm (see image below).  Each scale is shipped in a vinyl sheath.

A number of accessories are available for use with our scales (listed at the bottom of this page). These include magnetic holders, levels, and special adapters. Also included is our line of Invar extension tubing, available in many different configurations to suit your measurement needs.

Model numbers and lengths of standard scales