HP 6112A DC Power Supply is a precision power supply for 0-40 volts and 0-500mA current. It has a 5 digit digital input to select the precise output voltage. The HP611x is a whole series of such PSUs with different output voltages.
I bought this one after I was using the HP6111A for some time and was very happy with it. See here for details on that other PSU.
This unit has the crowbar option. It is not as clean, its overall optical state is not very well on arrival. Even inside it had dust and dirt. I gave it a good cleansing on arrival. On the inside, I’ve used compressed air. The result was quite ok.
Front. This device has a power switch with pilot lamp inside. Better than my HP 6111A.
Crowbar circuit with big thyristor.