This information from Busch + Müller works on the hub dynamo and has an on and off button. The front light can be pushed, waterproof and comes with holder.
Dimension of front light: 5 x 4 x 6.5 cm (L x W x D)
Size holder: 6 x 2 cm (L x B)
Type of lighting: led
The front light works on the hub dynamo.
Suitable for attachment to the front fork.
Equipped with an on / off button.