Golf club

A golf club head, comprising:

• a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, a striking surface positioned at a forward portion, an aft end positioned at a rear portion opposite the striking surface, and a hosel extending outward from the body proximate to a crown and heel transition region;
• wherein the striking surface of the club head body has a geometric center and a variable thickness with a maximum thickness greater than about 3.0 mm and a minimum thickness less than about 3.0 mm;
• wherein the club head body has:
• a face component made of a metal or metal alloy, and having surfaces defining the striking surface, a portion of the sole, a portion of the crown, a portion of the toe, and a portion of the heel;
• and a rear shell joined to the face component to provide a club head having an interior volume and having a rear portion including the aft end, the rear shell comprising at least two layers including an injection molded inner layer and an outer composite layer, wherein at least one of the inner layer or the outer layer comprises a polymeric material having:
• a tensile strength of from about 50 to about 1300 MPa, a tensile modulus of from about 2 to about 100 GPa, a flexural strength from about 50 to about 1000 MPa, a flexural modulus of from about 2 to about 120 GPa, and a tensile elongation of greater than about 1%;
• one or more rear weight ports located at the rear portion of the rear shell and proximate to the aft end, the one or more rear weight ports each configured to secure a replaceable weight, and defining a first central axis that extends through the sole portion and the crown portion of the golf club head;
• a slidable weight track located in the face component near the striking surface, the slidable weight track configured to secure one or more moveable weights;
• and a head origin defined as a position on the striking surface at approximately the geometric center, the head origin including a head origin x-axis, a head origin y-axis, and a head origin z-axis;
• wherein the head origin x-axis is tangential to the striking surface and generally parallel to a ground plane when the head is in an address position and a positive x-axis extends towards a heel portion;
• wherein the head origin y-axis extends perpendicular to the head origin x-axis and generally parallel to the ground plane when the head is in the address position and a positive y-axis extends from the striking surface and through the rear portion of the club head body;
• and wherein the head origin z-axis extends perpendicular to the ground plane, and perpendicular to both the head origin x-axis and y-axis when the head is in the address position and a positive z-axis extends from the head origin and generally upward;
• and wherein the golf club head has:
• a center of gravity with a head origin z-axis coordinate less than about 0 mm;
• a moment of inertia about a center of gravity x-axis (CG x-axis), wherein the CG x-axis is parallel to the head origin x-axis and passes through the center of gravity of the golf club head;
• and a moment of inertia about a center of gravity z-axis (CG z-axis), wherein the CG z-axis is parallel to the head origin z-axis and passes through the center of gravity of the golf club head;
• and wherein a golf club head moment of inertia about the CG x-axis is greater than 270 kgmm.sup.2 and a moment of inertia about the CG z-axis is greater than 440 kgmm.sup.2.