This Mechanical Dual Cylinder Thermostat combines both the controller and limit thermostats into one common unit, requiring only one direct immersion well. The controller and limit stat heads are provided with a jumper to minimise wiring. This Mechanical Dual Cylinder Thermostat controller has an external adjustment, while the limit has concealed adjustment with manual reset feature. This part is a direct replacement for UV Gold Cylinders, Everflo Cylinders and other leading manufacturers like Kingspan, Megaflo and Joule. Designed for use on an unvented cylinder with a thermostat pocket.