While previous satellite shifters were one unit, these newer ones consist of a shifting unit and a clamp, or band. In theory, you could actually stick the unit onto your handlebar using some strong double-sided tape,
Alternatively, slide the unit onto the band and then use the provided double-sided tape to attach it to the handlebar. You then wrap the bar tape over it to secure the shifter.
Availability
Shimano expects these units to be available September - October 2023 at the earliest.
Not for 105 Di2
Note that while these are part of the DURA-ACE R9200 series, they will work on the 12-speed Ultegra R8100 too, of course.
105 Shifters do not have extension ports, and these satellite shifters cannot be used with 105 shift levers.