The smallest and most compact dynamo powered taillight available, but don't be fooled by it's size, it meets all the requirements for brightness under the German road traffic regulations.
The mounting holes are 50mm apart, just like most other Busch & Müller taillights. The single LED glows bright red, so don't be fooled by the clear lens. And the optics in the lens spreads the red light across the width of the lens, so the driver behind you sees a lot more than just a point source of light. This has a standlight, so it will stay lit for several minutes after you stop.
This light should only be wired to a front 2.4 watt dynamo headlight.