Probably bordering on being off-topic, but Ive just put some temptags on my milk jugs. I find them really helpful. I have a Bezerra B3000 two group and the boiler has such a strong steam production, that the time needed to bring milk to temperature tends to be minimal. When Im making just a single coffee, I find that its difficult to produce decent froth and keep an eye on temperature at the same time.
The temptags allow me to completely focus on the frothing while the tag tells me exactly when the milk is at the right temperature.
They are really a great little tool to use.