130B-24 (In Photo) Features:

• Mahr Federal’s 130B-24 Gage Block Comparator is truly
  the preferred choice of all major calibration laboratories. It is
  specifically designed for the measurement of gage blocks by
  comparison, with no compromises made. The Model 130B-24 provides
  the ultimate in resolution and reproducibility for measurement of
  industry’s most important dimensional standards.
• Unique “Floating Measuring Frame” assures true point-to-point
  measurement.
• Single sensor design for the lowest possible electronic
  noise.
• Precise counterbalancing for control of measurement forces.
• Resolution of 0.1 microinch/0.001 micrometer
• Repeatability of 0.2 microinches/0.005 micrometers (6s < 1
  microinch/0.025 micrometer).
• Measurement capacity from 0.010″ through 4″ (0.25 mm through
  100 mm).
• Integrated measurement software and user interface.
• Built-in positioner for reproducible measurement
  locations.

130B-16 Features:

• Same highly linear, stable electronics as 130B-24.
• Designed for measuring blocks above 4.000″ (100 mm) but
  capable of checking shorter blocks as well.
• Linear ball slide for smoothly moving long gage blocks
  without danger of tipping them over.
• Large platen area for staging blocks before measurement –
  critical to achieving thermal equilibrium with the gage.
• Fully counterbalanced “floating measurement frame” to isolate
  measurements from vibration.
• Open frame design allows comparison measurement of large
  disks, up to 24″ in diameter.
• Can be operated from the same computer as 130B-24.
• Scale on left-hand post allows rough positioning, and
  micrometer-style spindle allows smooth, easy mechanical
  fine-adjustment.