Here's another item that came with my grandfather's parts.
You can pull the top up and underneath are four glass wet cells.
The tag says "The Clyde" Magneto re-charger and tester. Manufactured by the Magnetizer Manufacturing Co. of Los Angeles CA.
Here is a previous thread on the subject from Jan 2009 (2008 forum)
http://www.mtfca.com/discus/messages/50893/79424.html?1232838186
Regards
Art