Plus-1 Extension for Tight Stack Bike Rack (1st Generation)
 
Add 1 bike to the end of the TS-4 rack.
Can be used on either side.
Add 2 extensions, 1 on each side, for up to 6 bikes on one rack.
 
For use with TS-4 Version 1 Only. Not compatible with TS-4 V2.
 
Available for shipping to the USA only.
 
For more info, click here