This is a box to mount some toggle switches in a vehicle or boat or wherever you need them. It has one larger hole to run one power wire in and five smaller holes to run your wires out to your accessories or relays. The box that is for LEDs has an additional hole to run a ground wire out for your 5mm LEDs. I used #4 sheet metal screws to attach the lid but you may be able to use 3mm screws as well.