Although this is NOT a Brompton product, we have found these mirrors to be ideal for use with Brompton M type, H Type and S type handlebars. Used by ourselves, is unobtrusive and does not affect the fold. Once you have set the position, there is no need to move the mirror. Gives vital vision of traffic approaching behind. Slightly convex mirror give wide angle view. Head swivels on balljoint to give easy final adjustment. Fits inside handlebar and tightens with a singe screw. It is necesary to cut and remove the end of the grip, the bracket however provides a good clean finish as it is recessed approx 4mm to allow the end of the grip to insert inside. This ensures a pleasing appearance and further stabilizes the mirror. The mirror does not impede the fold in any way, and it is not necessary to change it's position at all every time you fold the bike.