Rockwell 31R Vintage CalculatorSlide Rule Memory. All calculators are unsold original stock from a local stationers.Please see other vintage calculator's listed today. From a smoke free home. The item "Rockwell 31R Vintage Calculator Slide Rule Memory" is in sale since Friday, July 31, 2020. This item is in the category "Computers/Tablets & Networking\Vintage Computing\Other Vintage Computing". The seller is "wakeycats14" and is located in England. This item can be shipped worldwide.