Topeak additional water bottle Cage Mount
This bottle cage mount fits onto either your handlebar or seatpost, so you can then fix bottle cage onto the mount.
The mounting loop fits handlebars or seatposts with a diameter of 22 - 38 mm and the shim is included. This mount weighs 45 g.
We fitted this to one of our Brompton stem's, it was very tricky to fit!. The mounting loop has four holes which fit different diameters, the loop wraps round and then is bolted in place. The shim included was not thick enough to fix the mount in place. So we used an old inner tube instead. Once fitted it does work well and you can still fold the Brompton with a water bottle in place. We did also fit this to a seatpost and it was a lot easier.
so we used an old inner tube instead.
Simply requires a 4 mm Allen / hex key to fit (and probably a pair of pliers to get a firm grip on the securing band)
Bottle cage not included
Topeak call this a CageMount
Can be useful for Zwift if you want to mount a water bottle on the handlebars for easy access