4 X AirFlow Brompton Easy Wheels, Black (2 sets) Unique easy wheels for Brompton, adjustable from 34mm to 76mm. I just bought these in Singapore, but I've decided not to use them. I'm using wheel extenders, and the easy wheels on the extender's extension arm rotate freely, so they don't match the size of the other wheels! However, if you're not using wheel extenders, these are really great! See: https://www.fantastic4toys.com/products/airflow-easy-wheels-for-brompton-bicycle?_pos=1&_sid=ce15e23b0&_ss=r