Precise Horizontal Digital Readout Scale 32" 

It can be on almost any surface.
With SPC output.
Resolution .0005"/0.01mm.
Accuracy +.001/1+0.03mm
LCD unit displays "E-50" for movement error.
Unit comes with 2 mounting brackets and EZ mount bracket kit.
It offers the user precise linear measurement capabilities.
One SR44 1.5V battery is supplied.
Note: sliding unit can be moved as fast as 40" per second.