A new US FTC filing made by Sony appears to reveal what may well be a USB Bluetooth adapter to enable the use of the PS4's DualShock 4 controllers on PC.
The filing – spotted by DualShockers – features the following image. Looks a lot like a dongle to us.
Microsoft's Xbox controllers have for a long time been compatible with PCs, and the upcoming new controller features Bluetooth for native support for Windows 10 PCs, phones and tablets.
With upwards of 40 million DualShock 4 controllers in the hands of gamers an adapter for official support on PC could prove popular.