A crystal detector in commercial form from the 1960's. The whisker is a self-bent copper wire spring. It is placed in a ball joint to provide maximum mechanical flexibility. The crystal was found on a trip in the mountains. The background is a paper with a 5 mm raster. Own photography by PeterFrankfurt 15:44, 25 February 2007 (UTC)
{{Information |Description=A crystal detector in commercial form from the 1960's. The whisker is a self-bent copper wire spring. It is placed in a ball joint to provide maximum mechanical flexibility. The crystal was found on a trip in the mountains. The