For Maxon BikeDrive AIR systems (e.g. the E-Menace). Not for the Paratu CP SL or Paratu CP LR — those use the click-fix version (incl. 45–90° cable).
The range extender adds 250 Wh of extra battery capacity, weighs 1.6 kg and charges the main battery while you ride. It mounts on the bottle-cage mounts with the range extender cage and rubber strap. The connecting cable locks with a bayonet closure (turn until it clicks).
See the range extender manual (AIR + AIR S).