This Biktrix Replacement BATTERY PACK, Range Extender Kit for Duo Series is a secondary battery on the Juggernaut Duo series bikes along with the Juggernaut FS Pro 2/3.

Use this battery if you want to ride even further than you can with just the internal hidden battery.

A high-quality design and many power options provides reliable power and range to extend your bicycle ride.

Fits:

• 52V16Ah / 52V17Ah Batteries incompatible with 17" Medium Frame
• 52V19Ah / 52V21Ah Batteries incompatible with 17" Medium Frame
• 52V16Ah / 52V17Ah Batteries only compatible with 20" XL Frame
• 52V19Ah / 52V21Ah Batteries only compatible with Large Size Frame

Important: 

• This battery has 3 different case heights- the larger 17Ah and 21Ah models may not fit smaller Step-Over frame sizes.  Consult the pictures here for battery height and notes below for frame size compatibility.
• If you have a Juggernaut Duo Series bike you will need a Range Extender plate to connect your battery to the bike.  When buying your battery here the plate will be included.