SON Hub Connectors Home - PiggyBack Connector - Coaxial Junction Box 
Son lights that use the Coaxial junction box allow for quick and easy connections to an 'inline' accessory device- which operates independently from the lighting circuit. This means that the dynamo hubs output is shared between 3 possible devices- Front Light, Rear Light, and Accessory. We recommend using the SON 28 as the generator in this application as its higher output power will suit the addition of powering an accessory and lights simultaneously.

In order to connect an accessory to the coaxial junction box, the use of a male coaxial connector is required: