I purchased this from a slide rule museum on line. It was surplus to their collection and in very good condition. Not very many young people have seen one or even know what it does. You do see them from time to time in old sci-fi movies. In a SHTF or EMP situation I'll never have to worry about this failing. Also doesn't need batteries either.
A training manual from Picket.
Little known facts that the Apollo moon missions carried slide rules on board as a backup in case of complete failure of the on-board computer system.