Duke is the first RRM3 autorigged character available for purchase.

Check out this brief demo of Duke's functionality 
 
Duke is a dog with all the bells and whistles you would expect from Rapid Rig: Modular including:
Joint-based face rig
Dynamic ears and tail
Stretchy spine, neck, tail and legs
Movable pivots
IK/FK legs, spine and neck
 
If you have RRM3, you will be able to use the following features:
RRM3 Selector (layout coming soon)
IK/FK matching
Space Switch matching
Pose and animation mirroring
Selecting Controls
Resetting Controls