thank you, that is the one! unlike the others, i never owned it originally. i bought it maybe 6 or 8 years ago on ebay. back in the age of apple ][, DOS and the like, i can imagine how it might have been quite a useful tool calculator.

oh, i also have a machinists calculator. it can do specific calcs like speeds and feeds, bolt pattern spacing, inch/metric conversion, etc. i rarely use that one too, but it's nice. i love how it has "adj", "opp", "hyp" markings for trig functions.