The woman helping me search for my car keys in the restaurant’s parking lot was wearing her own keys on a lanyard around her neck. Dangling alongside her keys was a square matchbook-size device.

If I’d had one of those, I could have used my smartphone to page my keys through a simple Bluetooth app.

I now have my own 1.6-inch-square Tile Pro Bluetooth Tracker tethered to my car keys (eventually found), my purse, eyeglass case, camera strap, and backpack.

Set up is simple. Download the Tile App for iOS or Android mobile devices — the website lists compatible devices — pair the Tiles to remain connected on your iOS (up to eight) or Android (up to four) device and name each (car keys, camera), and you’re set.

Click the app’s “find” function to page an object within up to a 400-foot Bluetooth range, and its guardian Tile will sound loudly, the indicator on the app glowing brighter as you get closer.

If the item is out of range, a map displays the last location the app made contact with it. Further afield, a Community Find feature lets you enlist all Tile apps everywhere in the search. If anyone running the app in the background passes within Bluetooth range of your lost object, you’ll get an anonymous alert mapping the location.

Tiles can find your cellphone too, so long as the app is running in the background. Clicking twice on the center button triggers a connected phone within Bluetooth range to ring at full-volume, even if the sound is muted or set on vibrate. The Tile website can locate linked mobile devices in any browser, though not actual Tile Trackers (which need the mobile app Bluetooth connection).

The Tile Pro weighs half an ounce and includes a replaceable round CR 2032 lithium battery.

The Tile Pro is about $35; a two-pack of one black and one white device, $60; four-pack with two of each color, $100 at thetileapp.com.