This handy fitting enables you to position a USB outlet under a wooden, fibreglass or metal dashboard complete with ruber plug moisture/dust cover. Alternatively, you can remove the actual USB insert to panel mount the USB socket. The insert requires a 22mm dia hole but it will go through upto 38mm of panel so your panel can be wood if necessary. This is a very versatile fitting and you have to see it to appreciate what it is capable of.