Bing 64 primer port heater?

[wildirishtime]

I've seen the 'side-mount' heaters for Bing carbs on Barnstormers, but anyone seen the primer port heaters for sale anywhere? Do they not work well? (we can skip the part of the conversation about not needing them, it's just 'backup' if you ask me, but I wouldn't mind having them if they're affordable and available.

[Mnflyer]

Hi I thought about them for my plane and the information I got was they have to be turned on from warm up and until you shut the engine down they do work will keep the crabs from forming ice but are to slow to work if ice has already formed. The best way to install the is to have the carbs off so you can easily install them very easy to break them and they are not cheap, but they do work.