The Back Bar resembles a weightlifting belt and has a 1/4-20 attachment for the invisible selfie stick. The design is similar to the Sail Video Systems mount, which costs hundreds more.
In the video, you can see Pepe adjust the view from rear, to side, to front. Pepe also posted a video while walking and running.
Note that the Xiaomi’s stabilization is nowhere as good as that of the One X. I ordered the BackBar and will post a test with the One X. In the meantime, if you want more 360 camera tips, subscribe to 360 Tips & Tricks. The Insta360 Back Bar is $33 + shipping and is currently in stock at Insta360’s store.