ID: 
2067
Maker's Name: 
Willard Storage Battery Co., Cleveland, Ohio, USA
Where made: 
USA
circa 1927

The Willard Colloidal Rectifier has two electrodes, one aluminium and the other probably lead, immersed in a solution of ammonium phosphate with other chemicals to optimise the process (see patent).

This one has never been used so that the chemicals are still in the original paper bag inside the glass container.

These rectifiers were used, connected directly to 110VAC  mains, for charging 'B' (typically 90-135V) batteries for radios.