It is expensive, but kind of cool. It's been too long ago for me to remember my conversation with Doug at ERA and the reason the sandwich thermostat wouldn't work with my remote filter, but had ERA offered an option for a switch like that on top, or on the side, of my filter adapter pictured below I would certainly have gone for it. Anything under $500 for that seems like a reasonable price, I doubt I would have gone for much over that (and truthfully I don't even need it).
