Abstract: A golf club head includes a head body having a crown, sole and skirt therebetween, the head body defining an opening in a front portion and having a frame support around the periphery of the opening. A face plate is mounted within the opening and has a transition radius along one or more edges to at least partially wrap around one or more of the crown, sole and skirt. The head includes thin wall zones in the crown and skirt, a hosel flush with the crown and a weight mounted in the sole proximate to the face plate, such that the golf club head has a center of gravity located relatively low and forward in proximity to the face plate.

Abstract: A golf club head is described having a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening. The golf club head also includes a face insert support structure located at the front opening. The support structure includes a rear support member. The rear support member includes a support portion interior surface contour defining an apex point and an undercut distance in an undercut region within at least one major or minor plane. A non-undercut region is located in at least one major or minor plane intersecting the crown to face transition region.

Abstract: A golf club head is described having a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening. The golf club head also includes a face insert support structure located at the front opening. The support structure includes a rear support member. The rear support member includes a support portion interior surface contour defining an apex point and an undercut distance in an undercut region within at least one major or minor plane. A non-undercut region is located in at least one major or minor plane intersecting the crown to face transition region.

Abstract: A golf club head is described having a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening. The golf club head also includes a face insert support structure located at the front opening. The support structure includes a rear support member. The rear support member includes a support portion interior surface contour defining an apex point and an undercut distance in an undercut region within at least one major or minor plane. A non-undercut region is located in at least one major or minor plane intersecting the crown to face transition region.

Abstract: An adjustable length golf club shaft having a grip portion with an end point is disclosed. A locking element is located within the grip portion and a lower shaft having an inner surface that is in frictional contact with the locking element is also disclosed. The locking element is configured to engage the inner surface of the lower shaft. A total length of the golf club shaft is adjustable by a distance of at least one inch and a total weight of the golf club shaft in a weight zone is less than 110 g. The weight zone is defined as a region of the golf club shaft extending from the end point of the grip portion up to 11? along a central axis of the golf club shaft toward a tip portion of the shaft.

Abstract: A golf club head with a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening is described. A face insert support structure is located at the front opening. The support structure includes a peripheral member and a rear support member. The rear support member has a front surface and a rear surface. A face insert is attached at the front opening and closes the front opening of the body. An undercut fill structure is attached to a portion of the rear surface of the rear support member.

Abstract: A golf club head is described having a body defining an interior cavity and comprising a heel portion, a toe portion, and a sole portion positioned at a bottom portion of the golf club head, and a crown positioned at a top portion. The body has a forward portion and a rearward portion. A face is positioned at the forward portion of the body. The face has a center face location and includes a center face characteristic time. An off-center location on the face is located at about ?40 mm in a heel direction away from the center face location. The off-center location has an off-center characteristic time of at least 80% of the center face characteristic time.

Abstract: Golf club heads are described comprising a striking surface that includes a center zone that is free of scorelines and an impact zone having an impact zone area, Aiz, and having a plurality of scorelines in the impact zone having an impact zone scoreline area, Asliz, such that a ratio Asliz/Aiz is at least 0.10.

Abstract: A golf club head is described having a body defining an interior cavity and comprising a heel portion, a toe portion, and a sole portion positioned at a bottom portion of the golf club head, and a crown positioned at a top portion. The body has a forward portion and a rearward portion. A face is positioned at the forward portion of the body. The face has a center face location and includes a center face characteristic time. An off-center location on the face is located at about ?40 mm in a heel direction away from the center face location. The off-center location has an off-center characteristic time of at least 80% of the center face characteristic time.

Abstract: A golf club head is described having a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening. The golf club head also includes a face insert support structure located at the front opening. The support structure includes a rear support member. The rear support member includes a support portion interior surface contour defining an apex point and an undercut distance in an undercut region within at least one major or minor plane. A non-undercut region is located in at least one major or minor plane intersecting the crown to face transition region.

Abstract: A golf club head includes a club body including a crown, a sole, a skirt disposed between and connecting the crown and the sole and a face portion connected to a front end of the club body. The face portion includes a geometric center defining the origin of a coordinate system when the golf club head is ideally positioned, the coordinate system including an x-axis being tangent to the face portion at the origin and parallel to a ground plane, a y-axis intersecting the origin being parallel to the ground plane and orthogonal to the x-axis, and a z-axis intersecting the origin being orthogonal to both the x-axis and the y-axis. The golf club head defines a center of gravity CG, the CG being a distance CGY from the origin as measured along the y-axis and a distance CGZ from the origin as measured along the z-axis.

Abstract: A golf club head is described having a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening. The golf club head also includes a face insert support structure located at the front opening. The support structure includes a rear support member. The rear support member includes a support portion interior surface contour defining an apex point and an undercut distance in an undercut region within at least one major or minor plane. A non-undercut region is located in at least one major or minor plane intersecting the crown to face transition region.

Abstract: An adjustable length golf club shaft having a grip portion with an end point is disclosed. A locking element is located within the grip portion and a lower shaft having an inner surface that is in frictional contact with the locking element is also disclosed. The locking element is configured to engage the inner surface of the lower shaft. A total length of the golf club shaft is adjustable by a distance of at least one inch and a total weight of the golf club shaft in a weight zone is less than 110 g. The weight zone is defined as a region of the golf club shaft extending from the end point of the grip portion up to 11? along a central axis of the golf club shaft toward a tip portion of the shaft.

Abstract: An adjustable length golf club shaft having a grip portion with an end point is disclosed. A locking element is located within the grip portion and a lower shaft having an inner surface that is in frictional contact with the locking element is also disclosed. The locking element is configured to engage the inner surface of the lower shaft. A total length of the golf club shaft is adjustable by a distance of at least one inch and a total weight of the golf club shaft in a weight zone is less than 110 g. The weight zone is defined as a region of the golf club shaft extending from the end point of the grip portion up to 11? along a central axis of the golf club shaft toward a tip portion of the shaft.

Abstract: A golf club head with a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening is described. A face insert support structure is located at the front opening. The support structure includes a peripheral member and a rear support member. The rear support member has a front surface and a rear surface. A face insert is attached at the front opening and closes the front opening of the body. An undercut fill structure is attached to a portion of the rear surface of the rear support member.

Abstract: A golf club head is described having a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening. The golf club head also includes a face insert support structure located at the front opening. The support structure includes a rear support member. The rear support member includes a support portion interior surface contour defining an apex point and an undercut distance in an undercut region within at least one major or minor plane. A non-undercut region is located in at least one major or minor plane intersecting the crown to face transition region.

Abstract: A golf club head includes a head body having a crown, sole and skirt therebetween, the head body defining an opening in a front portion and having a frame support around the periphery of the opening. A face plate is mounted within the opening and has a transition radius along one or more edges to at least partially wrap around one or more of the crown, sole and skirt. The head includes thin wall zones in the crown and skirt, a hosel flush with the crown and a weight mounted in the sole proximate to the face plate, such that the golf club head has a center of gravity located relatively low and forward in proximity to the face plate.

Abstract: An adjustable length golf club shaft having a grip portion with an end point is disclosed. A locking element is located within the grip portion and a lower shaft having an inner surface that is in frictional contact with the locking element is also disclosed. The locking element is configured to engage the inner surface of the lower shaft. A total length of the golf club shaft is adjustable by a distance of at least one inch and a total weight of the golf club shaft in a weight zone is less than 110 g. The weight zone is defined as a region of the golf club shaft extending from the end point of the grip portion up to 11? along a central axis of the golf club shaft toward a tip portion of the shaft.

Abstract: A golf club head with a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, and a front opening is described. A face insert support structure is located at the front opening. The support structure includes a peripheral member and a rear support member. The rear support member has a front surface and a rear surface. A face insert is attached at the front opening and closes the front opening of the body. An undercut fill structure is attached to a portion of the rear surface of the rear support member.

Abstract: A golf club head having good forgiveness and playability characteristics includes a body defining an interior cavity. The body includes a sole positioned at a bottom portion of the golf club head, a crown positioned at a top portion, a skirt positioned around a periphery between the sole and crown, and a strike face positioned at the front of the body. The body has a forward section, a mid-section and a back section. The mass of the forward section is at least as great as the combined mass of the mid-section and back section and the mass ratio of the back section to the mid-section is greater than 80%. Some embodiments of the club head include lightweight panels positioned within openings formed in the sole and crown of the body.