Prototype Power Supply / Armdroid 1
Model P402 (UK specification) / Armdroid 1
This model when measured with my digital multimeter is reading 15.13 Volts. Presumably, the voltage was increased from 12v to 15v in an attempt to prevent the motors from struggling.
Interestingly, Adman was also responsible for manufacturing a Speech Synthesizer product for the C64/VIC20 back in the early 1980s