Smart phones/mobile phones – most phones will support both HFP and A2DP.
GPS – Most motorcycle GPS devices will support HFP (some with additional A2DP support). Most car-GPS devices will not pair with a headset.
Bike’s On Board Audio – A2DP support. For example, BMW and Triumph bikes have on-board audio with Bluetooth.
Bluetooth Adapters and Dongles – A2DP. Sena has a 2-way radio adapter (the SR10), and it uses HFP. The Sena SM10 uses A2DP.