Rockford Fosgate Universal USB Port This Universal USB Port connects to any Rockford Fosgate PMX source unit equipped with a USB input jack and is Element Ready for protection against environmental contaminants. The stainless steel USB connections at both ends ensures it remains corrosion free, and the spring-loaded door is Ip67 certified to keep access to the port water-tight and dust proof. Installation simply requires a 7/8 hole, and includes a durable plastic nut with Posi-Lock design to mount to any surface up to 1-1/4 thick.