Best Relay

The Shelly 1PM Gen3 is a compact Wi-Fi relay with built-in power metering, the third-generation successor to one of the most popular DIY smart relays ever made. It installs behind a wall switch or outlet, switches loads up to 16 amps on 110-240 volt AC circuits, and continuously reports active power and accumulated energy use — a smart switch and an energy monitor combined in a single flush-mount module roughly 41 by 36 by 17 millimeters.

The Zooz ZEN55 800LR DC Signal Sensor solves a narrow but valuable problem: getting your hardwired smoke and carbon monoxide alarms onto your smart home without replacing them. It wires into the interconnect circuit that hardwired alarms already use to trigger one another, listens for the DC signal that alarms place on that wire, and translates it into distinct Z-Wave smoke and CO notifications that your hub can act on.