The Hybrid On-Deck Bat is designed to give two distinct feels by changing the moment of inertia (MOI) of the bat depending on which handle is held. 
 
When the traditional handle is held, there is a weight secured to the far end, providing the feel of an overload bat (not an extremely heavy traditional on-deck bat). This difference gives the batter the same feel as their overload bat and helps provide the feel they are used to. However, as research shows that swinging a lighter bat can help prepare the body fire, a simple flip of the bat can get an underload feel with some weight below the knob to reinforce proper slotting. 
 
This tool is a great way to provide different feels and ensure you are ready to step into the batter's box.