Patent ID: 7938739

Claim:
A golf club head comprising: a strike face; a back face opposite the strike face; a heel region; a toe region opposite the heel region; a cavity integral with the golf club head; and a filler material located in the cavity, the filler material comprising a density less than a density of the golf club head; wherein: the cavity comprises a back wall integral with the back face; the cavity comprises an interior with a substantially tubular shape defined at least in part by the back wall and extending from the heel region to the toe region; the cavity is substantially sealed off by the back wall from a rear exterior of the golf club head; the cavity extends along a lower portion of the back face of the golf club head; the cavity extends approximately parallel to the strike face; the cavity is approximately symmetrical about a centerline that bisects the golf club head between the heel region and the toe region; the filler material comprises at least one of: a first filler density that decreases along the cavity from the heel region to the centerline; or a second filler density that decreases along the cavity from the toe region to the centerline.