Thunderwulf

Hey all. Just trying to find out if there is some kind of device out there that is essentially a wireless tape measure? Here are the details of what I would needed it to do.. 1. It should be two devices. A base unit and a satellite unit. The base unit would have a display that gives a simple read-out of the distance between itself and the satellite unit. 2. The satellite unit should be small and compact. 3. It would not be line of sight (even though there will be no obstructions) so it would probably have to be radio based? If anyone has seen anything like this (either as plans or pre-made) Id really appreciate it. Would rather not have to have something like this built from scratch. :)