This thermal fuse is stock on all our Quick Mill machines equipped with an Ulka 52 watt vibratory pump: Andreja Premium, Anita, and the Alexia. It's a simple fuse designed to protect your pump from burning up. If a vibe pump continues to run non stop for more than 15 minutes, you can burn out the coil, rendering the pump useless. Before that happens, with one of these fuses installed on you pump, power will be cut to the pump before any damage occurs. Once the coil cools down, the fuse will close and power will resume to your pump.