Sock. In a Nigheyes pouch that I carry a pair of Leathermen tools [Crunch and Original] I daily carry a magnet. It is on one of those extendable pointers. About 7 inches collapsed and 27 inches pulled out. It is designed as a magnetic pickup tool. It is rated to lift 8 to 10 pounds. I replaced the pocket clip with a screw eye so I could easily attach some cordage to reach even lower. The initial idea was if I ever dropped or spotted something metallic I could go fishing. The magnet could also be used to magnetize a piece of metal like a sewing needle as a backup compass.

Well being ready payed off. Dropped my keys down a drain grating. Too narrow to reach through and too deep reach. 30 second later I had my keys back. Came in very handy.