Abstract: A putter is disclosed having a ball mark assembly integrated within the body of the club head. The ball mark assembly holds a ball positioning marker when it is not being used to indicate the position of a golf ball. The ball mark assembly includes a housing which houses a spring. The spring forces the ball position marker to abut a surface of the housing when it is inserted into its stored position. A magnet is secured to the end of the spring and, when the ball position marker is ferromagnetic in material, applies a retention force to it adding to the force required to remove the ball position marker from the housing. An indented guide further protects the ball position marker from being dislodged inadvertently. The housing and guide are spaced equidistantly from an outward surface and an inward surface to ensure proper balance and alignment of the putter while a golfer is putting. Different sized ball position markers may be used to change the weighting of the putter as desired by the golfer.

Abstract: This invention relates to collagen compositions and methods of preparing such compositions. This invention also relates to a novel source of collagen, the common digital extensor tendon.