This B+M battery powered tail light bolts a 50mm or 80mm bolt pattern rack mount. Two extremely bright LEDs shine to both sides and backwards, giving a 220 degree angle of visibility. It has a large reflector and burns steady only - as required by German law where it is manufactured. It does not have a blinky mode.
The DToplight XS Permanent is an excellent tail light for the BROMPTON. It mounts on the existing reflector mount or rear rack and is protected when the bike is folded.