https://www.pcgamer.com/htcs-vive-wireless-adapter-is-now-available-to-preorder-starting-at-dollar300/

HTC is now accepting preorders for a wireless kit that is compatible with its Vive and Vive Pro VR headsets, though it's not exactly a cheap accessory. Cutting the cord will set you back $299.99 (£299), plus another $60 (£65) if you own a Vive Pro.

The up-charge for the Vive Pro is for an attachment kit that is necessary to mount it to the headset. Or put another way, it's an adapter for the adapter.