The Compu-Cal Pro Edition Users Manual Version 6.0 Lot of 2 is a vintage software product from Camde Corporation, located in the United States. This manual is specifically designed for users of the Compu-Cal Pro Edition software, providing detailed instructions and guidance on how to use the program. With a vintage appeal and a focus on software training, this product is a valuable addition for those interested in retro computing and historical technology. And calculator has not been tested. Not sure how to put batteries in it.