I think I caught a whiff of "universal" reading someone's story of getting a replacement coolant sensor. The LH2.0 and LH2.2 sensors are blue, having one element not internally grounded. The LH2.4 and presumably Regina sensors are black, having two elements, with a common internal ground and a higher price tag.

As the thermistor elements are the same type in both, the black sensor would work in the blue application, just not the other way 'round. Makes for less items to stock, and more money to be spent.