USB LINK connection. Plugs into Mac/PC. You can NOT connect your Kestrel 5000 series to your Mac/PC via bluetooth without this Kestrel LINK Dongle. Unfortunately, you can not just buy a regular LINK dongle as you might suspect on Amazon a computer site, they won't work... it MUST be the Kestrel LINK Dongle as sold here. We wish that were different, but this is the one. One work around we've found if you don't want to get this, is to export your data to your smartphone (Android or iPhone) with the Kestrel Connect App, and then email the data to your Mac/PC.