EGO Simmerstats 50.57076.070 and 50.57071.010 13A, 240v work by means of a bi-metal strip that flexes under temperature to make a circuit switching on and off depending on the knob position. Two standard shaft sizes are available 6mm and 4.7mm, both with different mounting options, knobs and bezels to suit are available.
Use these to control the temperature on equipment such as Bain-Maries and hot cupboards. They control the temperature without any direct temperature measurement.
P1 – Live
P2 – Neutral
2 & 4 are the load (not polarity dependent)