At a glance Expert's Rating Pros ・Petite, unobtrusive hardware ・Wi-Fi connectivity and interconnected features work well ...

Roost impressed us last year with its Wi-Fi-enabled 9-volt Smart Battery ($35, available at Amazon.com). Put one in your smoke detector and it will send you an alert when the smoke detector senses ...

But it's not reliable without a battery backup says Joel Lavender with Dallas Fire-Rescue. "We have storms here in North Texas there may be a fire or accident outside that may knock out electrical ...

At $35, it's an easier splurge than the similarly aimed $100 Nest Protect , and a more cost-friendly way to smarten up your whole home's worth of detectors as well. The Roost Smart Battery isn't ...