Simply the best Sonos One wall mount on the market. Not cheap, but highly recommended. It's very sturdy, comes with all wall mounting equipment and you can mount upside down so you can access the buttons from underneath (but you can mount right way up if you want also). Highly recommended.
We bought these to mount our new Sonos One's in our new room extension, they look absolutely amazing and perform well. They were super easy to set up and have not faltered at all since (obviously!). Would highly recommend buying these if you plan to mount your Sonos One's to a wall or ceiling.