We have a number of these assemblies in stock. All contain 2 motors
(Tsukasa 24V geared DC motors, part number TG-05C-SG-75-KA, gear ratio 1/75),
2 encoders (Copal magnetic encoders, part number RMS20-250-201-1),
and 2 potentiometers (Copal 10-turn 1k potentiometers, part number M22S10).
The physical layout of the assemblies varies slightly from unit to unit, as shown in the photos below.
Available upon request, we also have some nearly identical units that contain Tsukasa TG-05P-SG-75-KA or TG-05L-SG-75-KA motors.