Vintage Keithley, API Analog meter, FS -50uA to + 50uA, TESTED, Center Null

Description

Vintage Keithley Instruments, manufactured by Assembly Products, Inc., Analog meter, FS -50uA to + 50uA, Zero Center.
Meter has a mirrored backround to eliminate parallax, and is very sensitive at 50 micro volts full scale!
The meter does not have a box. It has been TESTED and VERIFIED and is very accurate and repeatable. Refer to the test photo's for meter response.
Note: The glass window does come off if the buyer wants to provide their own custom backround and scale. Refer to the photo showing the glass removed.  Overall size of meter front frame is 3.5" x 2". Overall depth, frame to back of meter is 2.25".
NOTE:
This is a great meter if you plan to use it on a model train board. Because it is zero center meter, the scale could be printed that would indicate REVERSE MPH / STOPPED / FORWARD MPH.
Or for that matter, any project that requires a center 'OFF' position display. This is the last one that I have with this 50 uV full scale sensitivity.