Robust design and high grade materials meet the stringent demands of today's service professional. In design, we specify custom wax formulations that will expand when heated, activate a snap action electrical contact and transfer the electrical signal to the fan controller. In manufacturing, we custom form the wax pellets for different temperature range specifications. All units are calibrated & d to confirm switch actuation at their specified temperature. The switch is designed using a formed bimetallic contact arm. The bimetal contact movement is achieved using the different expansion rates of two metals fused together. This is a creep action device, provides precise performance. In production, all thermal switches are factory-calibrated to make electrical contact at the specified lower-temperature set point. As a global manufacturer of original equipment ignition products, we maintain complete quality control throughout the manufacturing process from componentry to finished product.