see this item with many photos at.... http://smecc.org/burroughs_what-is-it_page_-_artifacts_needing_identificatio n!.htm item C_O_S_T Comparator of System Timing Demo Kit? seems to be 2 of these in the pouch... pouch will not close with both so we have decided one board and one ruler is a duplicate. Maybe should should go to C.B.I if they do not have one? Burroughs COST - tell us about how this was used and any interesting stories .. This was in the Jack Aldrige collection Thanks, Ed Sharpe archivist for SMECC