Clip-on Aero Bar Satellite Shifter (12 speed)
The new SW-RS801-E satellite shifter was introduced in September 2022, about a year after Shimano released Ultegra R8100 / R9200 to the world. It comes with extra long wires (740mm), letting you install satellite shifters to clip-on aero bars.
These connect to the special Satellite Shifter port, only found on the Ultegra and Dura-Ace 12-speed shift levers. This is always the bottom port. They will not work in any regular SD300 port.
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.
These are sold as a pair, weigh 8.2g each, and come with a 740mm wire.
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.