Whilst skiing in deep powder even the best of skiers sometimes lose balance, turn too quickly or somehow fall over out of the blue. When in fluffy deep powder, it is extremely easy to lose a ski. Without a leash or ribbon, it might take anywhere from a few minutes to a few hours to find it, if in fact you do at all.
Leashes and ribbons can be used to try and prevent the problem of losing a ski, but, apart from being extremely fiddly, primitive and annoying, can in fact be very dangerous. The risk of the leash jerking the ski back into the direction of the skier and hitting them powerfully is a distinct possibility if the skier is in fact traveling reasonably quickly.
RESQSKI is a newly developed product that uses a radio transceiver to locate the ski very quickly, and, even though the chances of the ski going far away from you are small, can work from up to 50 metres away.