Attaches to Thule Bed Rider (e.g. 822XTR) (sold separately) to increase bike carrying capacity.

Locking Add-On Block for Pick-Up Truck Fork Mounted Bike Carrier 

The Thule Locking Bed Rider Add-On Block is the perfect solution for bike enthusiasts looking to increase their carrying capacity. This add-on block attaches easily to the Thule Bed Rider (sold separately) and allows you to safely and securely transport additional bikes on your truck bed.