Unknown Model Number
Older analog meter

IM 7001
Close-up of control panel.

IM 7001
New style contamination meter with digital display and two probes.

DT 7003 Probe & DT 7004 Probe
Used with both analog and digital contamination meters.
The DT 7003 is for use in air and the DT 7004 is for use in liquids.