This small option board is for DIY power source.
it’s ready made item and there is no need to soldering to use. You buy it then you can use it.
DIY power source come with 10 pin connectors. it provide +12V, GND and -12V. but this option board provid also +5V. it’s starndard 16 pin Euro Rack power line conncetor can be connected with this directly.
a single module that you get newly but you want it test before put it in your rack, that’s the time for this board. You can provid power source. to your single module.
you can get noise source as audio source for test from DIY power source, also. It’s getting to be your simple work bench.