Patent ID: 8876629

Claim:
A golf club head comprising: a hollow unitary shell including a metallic striking face, made out of a first material having a first density, forming at least one opening near a crown portion and a sole portion of said golf club head; at least one panel configured to cover said at least one opening; and a face backing layer, made out of second material having a second density, attached to an internal back surface of said striking face of said golf club head; wherein said golf club head has a volume of greater than about 400 cc and less than about 500 cc; wherein said second density is lower than said first density, wherein a thickness of said metallic striking face is between about 0.25 mm to about 0.45 mm, and wherein said golf club head has a first peak frequency to volume ratio of greater than about 7.0 hertz/cc and less than about 15.0 hertz/cc; said first peak frequency to volume ratio is defined as a first peak frequency of a signal power diagram of the sound of said golf club head as it impacts a golf ball, divided by a volume of said golf club head.