The Acer XV hybrids feature cup-face construction or where part of the faceplate wraps around and becomes incorporated into the sole, crown and skirt area of the head. This pushes the weld back away from the actual face so the areas around the perimeter could be made thinner creating more face deflection for higher ball speeds to areas other than the center of the face. Even when you miss-hit the ball, the XV with cup-face technology provides you that extra spring-like effect for longer shots. These also feature the same Power Chamber as the matching driver. In addition, these low profile heads coupled with the Gravity Port moved toward the face promotes a higher launch with lower spin. Stock screw is 7 grams and requires 4mm Allen wrench.