Notes: "1) An interesting slide rule using a rectangular channel for the slide with the slide held in by magnets 2) Several ITAB models were produced, this one apparently for radiator design. 3) Reference Peter Holland, 'Magnetic"" Slide Rules by ITAB, IM2006, Grefswald, 29.9 2006 4) Note the window on the reverse for additional scales on the back of the slide."