OK, not an electronic part But, technically, it makes resistors.. so Found these IBM Mark Sensing Pencil Leads at an Estate Sale today. Pretty neat. These were likely used in conjunction with,My spectrum analyzer 1.8 GHz with various options 004 (10 MHz precision reference) 103 Quasi peak detector with AM FM demodulation and 130 (low resolutions) Hopefully the device will work for a long time.,The Spectrum Show EP 103,IBM OS/2 Warp 3 was announced on 11 October 1994, 30 years ago today. Annoyed that I've misplaced the power supply to my IBM Thinkpad 755CV running OS/2 Warp as I know