ERA-EXKIT Wired Doorbell Range Extender - 4,000 ft. CoverageThe ERA EXKIT allows you to extend the listening range of a wired doorbell. Hear your doorbell downstairs, in a back office, garage or warehouse. Wire a small, wireless transmitter to your existing doorbell and pair the transmitter to the plugin receiver included in the kit. NOTE: This IS NOT a standalone product. It must be programmed to a compatible ERA receiver. Features The ERA EXTX transmitter is powered by a long lasting lithium battery with a