Cleveland Golf Men's CG 14 Tour Zip Satin Chrome Wedge Gelback, Cleveland Golf's lightweight, visco-elastic, vibration-damping material, is placed directly behind the hitting area of the clubface in the back cavity. Breakthrough milling technology creates pristine edges increasing "ZIP" and shot consistency-especially from poor lies. Conforms to 2010 USGA groove rule. Maximizes allowable groove dimensions while conforming to 2011 USGA groove requirements. Gelback is vibration-tuned to remove unwanted vibration on mis-hits while still allowing the player necessary feedback from the clubhead for a soft yet responsive feel.