Head's made a major change for the 2008-2009 season with their new AMP technology. The racquet head shape is slightly different than the Extreme and MX (closer to the liquid metal line head shape) and they all include their new revolutionary AMP technology. AMP is integrated into the critical throat area where traditionally power is lost during ball impact.  Lab testing confirms AMP technology delivers 20% more stiffness than conventional racquet design, resulting in more energy return. The uniquely designed dual beams work together creating a counterbalance effect for an explosive increase in raw power with every swing.