This is the fuse box from the Yak-18T. It's an aluminum enclosure packed full of genuine soviet fuses, relays, and wiring on the inside. These fuses protect the avionics and electronic instruments from further damage if they malfunction or if there is a wiring problem. It's important to note that these fuses cannot be reset when they blow, and must be replaced. Modern aircraft generally use circuit breakers that can be reset if needed.