Knowledge is the ultimate expedient redundancy. It weighs nothing and cost little. It can often be used on whatever happens to be around. <br><br>In this case the needle can be replaced with almost any long straight piece of steel that is light enough to be handled in this manner. The silk can be replaced by other fabrics or you could carry silk thread wound around you needles and have that available for re-magnetizing it as well as fixing you ripped skivvys. Anyone know the list of fabrics which will impart a sufficient static charge on the needle / straight pin / small nail / short steel wire? <br><br>If you have a lensatic orienteering compass in you pack you probably won't use the button compass in you PSK. OTOH if you lose the orienteering compass from your pack you would be glad to have the button compass in your PSK. If you lose your pack and psk it is handy to know how to pick up a small short length of steel and magnetize it and use it on water. In true wilderness the length of steel might be difficult to find but if you are standing beside a downed aircraft it shouldn't be too hard. <br><br>Is it pratical? Well, 'depends upon the options.