This is a case for storing excess cables around your workstation, or you can use it to store your earphones on the go. It has a simple construction that snaps together. There is a slot on the top piece that the bottom piece will snap into. Insert the cable into the groove on the bottom piece, align the top piece with the bottom piece, press them together until they click. Rotate the bottom piece using the finger tabs on the back of it to wind up the cable. Pull the ends of the cable to extend the cable.