How long is the cable from the back of the clamp to the computer? Noriko July 11, 2018 08:48 Updated Follow A. The USB cable is about 12” long. Related articles What kind of USB ports are these? Does this product on work with Macs or can it work with any other computer? Will this attach to all Mac computers? Does it come with a USB cable? Quick Guide Comments 0 comments Please sign in to leave a comment.