The present invention is directed to a golf club head comprising one or more center of gravity and bias adjustment features. In some embodiments, the golf club head comprises an elongated cartridge having one or more sockets or weight ports to receive weight plugs, the arrangement of which can be changed to adjust the mass properties of the golf club head. The orientation of the cartridge itself can also be reversed to adjust the mass properties. In other embodiments, the golf club head comprises at least one semicircular weight ring that extends around the rear portion of the golf club head, and is removable and replaceable to adjust the mass properties of the golf club head. In still other embodiments, these features are combined on one head.