That seems like a useful product as well, though I wouldn't imagine it would help for showers. I'd think the limit you would want for showers would be different from the limit you would want for your dishwasher, for example, or even your washing machine's hot mode.

This was basically a replacement for a shower's heat control knob. If I can't find it it's no big deal, since installation would be pretty expensive. I'd have to be able to get electrical power to the shower (safely). The installation in my old bathroom also involved something run to under the sink and connected to a 9V battery. That was there so that if the power went out, you could still turn the shower off