Bi-Metal-Switch-RVFM-P04061-A-This-bi-metal-switch-is-a-dramatic-demonstration-of-the-thermostat-principle-Consists-of-a-bi-metal-strip-mounted-on-a-base-Because-of-the-unequal-expansion-of-the-two-different-metals-the-bi-metal-strip-will-bend-to-open-or-close-the-circuit-&-the-light-bulb-lights-up-accordingly-RVFM-Bi-Metal-Switch