An interesting, illuminated Bakelite bell button. We wired this up to our bell tester set to 4 volts. We then took a step back and turned on the power and ... the button lit up, amazing. When we pressed the button the light went out and the bell rang. How the `mechanism` works is beyond our understanding as anything electrical is a black art to us. But work it does, dimly at 4 volts so could probably do with 6 or even 8 volts. Most low voltage be transformers have a selection of voltages available. LOW VOLTAGE APPLICATIONS ONLY. If in doubt consult a suitably qualified electrician. In pretty good condition with a couple of minor scuffs to the cover.