Do shark shields work?

These things seem to be an increasingly important part of equipment for Nor Cal fishing after July 4th!

Looks like I'm in the Majority with " Hope So... "

 Having felt that thing "Zap" me,  There is something going on there....

I heard that australian commercial divers are required to wear them by their insurance companies. i too have been zapped by my shark-shield and truly believe they work.  That is what i keep telling myself anyway.