These are rare late model 5101B's. Near the end of life of these products, Fluke modernized the front panel, changed the style of output jacks, front handles, etc. These units look much more modern and are more reliable than the average unit you will find on the used market.
The Fluke 5100B supplies AC & DC voltage, AC & DC current, and resistance for precise applications; such as calibration of digital multimeters.
▪ DC & AC Volts: 20 mV to 1100 V full scale (0.1 µV resolution)
▪ 50 Hz to 50 kHz frequency of standard unit
▪ DC & AC Current from 200 µA to 2A full scale
▪ 1 ohm to 10 Mohm resistance in decade steps
▪ Wideband option available
▪ HP-IB and Bit serial interface available
▪ Drivers incorporate it into an ATE system using Fluke's MET/CAL Software
OPTIONS available for an additional fee
Option 03 = Wideband AC Voltage
Option 05 = IEEE-488 Compatible Interface