My Jawbone Up3 kept falling off my wrist and this time I had no idea where I dropped it. I knew it was near my house because it would randomly connect to my phone from different areas in my house. I tried a few free apps and either they didn't find any signal (even when it was clearly connected to my iPhone) or they connected but would only show the change in signal strength (or RSSI) once every 3 or 4 minutes. Completely useless when walking around the house trying to ping it. I was hesitant to pay for an app (especially some for 4 or 5 bucks that seemed like scams) but this app's price was right at only a couple dollars. The app is simple and connected right away. The RSSI was converted into a simple graph which showed you how close you are to it. A couple tips: 1. Remember that the signal goes through most objects and can go through floors, ceilings, and walls. 2. Once you connect, remember to walk slowly with the phone held away from your body for maximum signal potential. 3. Despite other apps with icons that show a radar screen, all phones can only tell the signal strength of a passive device and don't work like radar showing you the exact location in comparison to you so be patient and think of what is around you, above you, below you, behind you, or in my case through heavy plaster walls, brick, and 15 feet across my driveway and wedged in the seat of my car.