One of these, we think, is the Belkin Break Free. It's a simple product that has a jack socket on one end and a plug on the other, with a magnetic connector in the middle. If tugged hard, the magnetic connection breaks, and prevents the cable being pulled from its socket. All the player has to do to re-make the connection is snap the two magnets back together.
It's aimed for use on stage, where it could prevent damage to the socket of a guitar or bass, in the event that the cable is tripped over or snagged. The powerful magnet makes a good connection, and snaps together in an instant.
Of course, these can be used in the studio too; instead of using a patch bay, cables can be snapped in and out of a mixing desk or rackmount processor, without having to completely remove and then re-insert the plug. They're due to become available soon, costing under $20 each.
Visit Belkin's web site and watch the video below for more.