Ok, so our 3 year old pos doorbell button already rotted, so I went to replace it with one from Lowes. The catch is the Lowes button says max 16 volts (I think all said this), but I tested the line and it's 21 volts. Is it safe to use, are there buttons that can handle more volts? I've gotten burned before using the wrong voltage/wattage things, so I don't want to just try it and create an electric hazzard. All the buttons online that I could find don't state the max wattage. What gives? I tested the voltage on the button wires themselves and coming off of the transformer.