We recently started selling the Minew F4, a quality tracking beacon with external on/off button, 85dBm buzzer and range of up to 50m. The battery last about 6 months. Minew have a video how to change the battery:
There’s a T-Finder iOS and Android app on the app stores but the intention is that this beacon will be used with your own apps and solutions using the supplied Android and iOS SDK.
View Tracker Beacons