A dongle is a small electronic device that is attached to your computer. When it is attached, FlowJo will be able to run on that computer. Because this is the most flexible option, dongles are the recommended choice for your first copy of FlowJo. Dongles allow you to run FlowJo on any PowerPC, including notebooks. 

Advantage:
-you can easily move a dongle and therefore run FlowJo on any computer

Disadvantage:
-if you lose the dongle, you will have to purchase a new one (at full price)

NOTE: FlowJo Version 4 uses a different USB dongle than Version 3 (instructions for dongle swap are included when you purchase an upgrade to v4). ADB dongles do not work with v4. FlowJo v4 runs on operating systems 8.6 and higher.