Finally. A phone mount specifically made for the Brompton folding bike.
Brompton Quad Lock Phone Mount the T Line - with phone mount adaptor
This kit comes with the Phone Mount that attaches to your Brompton and a Universal Adapter that sticks to the back of your phone or phone case.
Brompton Brompton Quad Lock Phone Mount 25.4mm with Universal Adaptor
Brompton Quad Lock - iPhone 11 Pro Max - Eh. : r/Brompton
My Bespoke M handlebar bridge with integrated Garmin & Quadlock mounts. Clean and minimalist , no unsightly rubberbands or outfront arms. : r/ Brompton
Brompton Quad Lock Phone Mount with Uni Adaptor - JV Bike
The Brompton Phone Mount
Brompton Quad Lock Phone Mount For T Line – With Adaptor - JV Bike
Quadlock Phone Mount, Brompton Phone Holder
Brompton Quad Lock Phone Mount - Clever Cycles Portland Ebike & Bicycle Store
Quad lock to Peak Design Adapter for Brompton
Brompton Quad Lock Phone Mount with Universal Adaptor : Automotive
strongest & most secure bike mount., Easy to attach & detach., BNIB Brompton Original & Authentic, Quadlock Handlebar Phone Mount, Handlebar mount
(No stock) BNIB Brompton Quad Lock Phone Mount - QuadLock