What Yamaha Say:
Introducing Yamaha Inpres DriveStar Driver, The newest Japan Only Inpres series.

Features & Benefits:

• BoostBox - Maximizes impact energy and converts it to muzzle velocity. Evolution of original muzzle speed-up technology "BOOSTRING" and "SPEEDBOX". The structure around the face suppresses unnecessary vibration at the time of impact and maximizes energy conversion to the initial velocity.
• Science of RBI - You can hit with the most flying RBI by scientific sensibility. Golfers tend to hit what they perceive as the "center of the head height" of the driver. Yamaha paid attention to this and designed the crown shape and face design so that the ball can be hit where it flies the farthest (= slightly above the center of the face).
• COUNTERWEIGHT SYSTEM - The key to flight and straightness is the lateral moment of inertia that is within the rule limit class. Approximately 25g of weight is optimally placed on the toe, back, and heel, centering on the center of gravity. This achieves a rule limit class lateral moment of inertia of 5570g cm2, creating overwhelming flight and straightness.
• "Good Face" - Clubs with a large moment of inertia generally tend to have a large projected area, but inpres DRIVESTAR has an orthodox shape that golfers can easily hold.