eBay is full of weird and random industrial modules. I saw this one, and since I couldn't find any data about it at all, I decided to buy one and reverse engineer it. Even after working out what it does, I'm not sure of the exact application. I think it may be intended as part of a sterilisation system for rooms, where a limit switch on the door breaks power to the circuit, and it has to be reset manually upon leaving the room. The relay circuit is particularly special for its use of a cheap, small and rugged component in place of a traditional hot-running mains voltage component. The high voltage circuit is using a VERY non-standard approach to minimise components. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- http://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.