I had always heard that there were only clear lids for cobalt Canton Electric jars.  It was accepted, common knowledge.  I was very surprised, then, when Al Vignon's collection went up for sale to find this Canton Electric with a cobalt lid - the only one known!  It's a bit different from the clear lid and with one unreinforced fin, I think it's a bit fragile which is perhaps why its use was discontinued.

The Electric jar is less showy than it's much deeper cousin the cobalt Canton Domestic.