Wedge type golf club head

1. A wedge type golf club head comprising:

a hosel;

a body attached to said hosel at a loft angle, wherein said body further comprises a hitting surface and a rear portion, said hitting surface defining a neutral axis perpendicular to a loft of said hitting surface and passing through an impact point on said hitting surface; and

a sole at a bottom of said body at least partially resting on a ground connecting said hitting surface and said rear portion,

wherein said rear portion further comprises at least one hollow chamber, and

wherein a center of gravity of said wedge type golf club head is substantially along and above said neutral axis.

2. The wedge type golf club head of claim 1 , wherein said at least one hollow chamber is filled with a second material having a density greater than a density of a remainder of said wedge type golf club head.

3. The wedge type golf club head of claim 2 , wherein a ratio of said density of said second material to said density of said remainder of said wedge type golf club head is greater than about 2.0.

4. The wedge type golf club head of claim 3 , wherein said ratio of said density of said second material to said density of said remainder of said wedge type golf club head is greater than about 2.25.

5. The wedge type golf club head of claim 4 , wherein said ratio of said density of said second material to said density of said remainder of said wedge type golf club head is greater than about 2.5.

6. The wedge type golf club head of claim 3 , wherein said density of said second material is about 19300 kg/cubic meters.

7. The wedge type golf club head of claim 1 , wherein said wedge type golf club head has a Performance Ratio of greater than about 530,000 rpm*mph;

wherein said Performance Ratio is defined as a launch angle multiplied by a ball speed multiplied by a backspin, all divided by said loft of said golf club head.

8. The wedge type golf club head of claim 1 , wherein said at least one chamber is located within a bottom segment of said rear portion.

9. The wedge type golf club head of claim 1 , wherein an upper segment of said rear portion has a thickness of greater than about 4.8 mm and less than about 7.1 mm.

10. The wedge type golf club head of claim 9 , wherein said upper segment of said rear portion has a thickness of greater than about 5.33 mm and less than about 6.6 mm.

11. The wedge type golf club head of claim 10 , wherein said upper segment of said rear portion has a thickness of about 5.84 mm.

12. The wedge type golf club head of claim 10 , wherein said golf club head has a center of gravity location that is between about 16 mm and 20 mm away from said ground.

13. The wedge type golf club head of claim 12 , wherein said golf club head has a center of gravity location that is between about 17 mm and 19 mm away from said ground.

14. The wedge type golf club head of claim 13 , wherein said golf club head has a center of gravity location that about 18 mm away from said ground.

15. A wedge type golf club head comprising:

a hosel;

a body attached to said hosel at a loft angle, wherein said body comprises a hitting surface and a rear portion, wherein said hitting surface defining a neutral axis perpendicular to a loft of said hitting surface and passing through an impact point on said hitting surface; and

a sole at a bottom of said body at least partially resting on a ground connecting said hitting surface and said rear portion,

wherein said loft angle is greater than about 45 degrees;

wherein an upper segment of said rear portion has a thickness of greater than about 4.8 mm and less than about 7.1 mm;

wherein said golf club head has a center of gravity location that is between about 16 mm and 20 mm away from said ground, and

wherein said center of gravity of said wedge type golf club head is located substantially along, and above said neutral axis.

16. The wedge type golf club head of claim 15 , wherein said wedge type golf club head has a Performance Ratio of greater than about 530,000 rpm*mph;

wherein said Performance Ratio is defined as a launch angle multiplied by a ball speed multiplied by a backspin, all divided by a loft of said golf club head.

17. The wedge type golf club head of claim 16 , wherein said rear portion further comprises at least one hollow chamber.

18. The wedge type golf club head of claim 17 , wherein said at least one hollow chamber is filled with a second material having a density greater than a density of a remainder of said wedge type golf club head.

19. A wedge type golf club head comprising:

a hosel;

a body attached to said hosel at a loft angle, wherein said body comprises a hitting surface and a rear portion; and

a sole at a bottom of said body at least partially resting on a ground connecting said hitting surface and said rear portion, said hitting surface defining a neutral axis perpendicular to a loft of said hitting surface and passing through an impact point on said hitting surface,

wherein said loft angle is greater than about 45 degrees;

wherein said golf club head has a center of gravity location that is between about 16 mm and 20 mm away from said ground;

wherein said wedge type golf club head has a Performance Ratio of greater than about 530,000 rpm*mph, wherein said Performance Ratio is defined as a launch angle multiplied by a ball speed multiplied by a backspin, all divided by a loft of said golf club head, and

wherein said center of gravity of said wedge type golf club head is substantially along, and above said neutral axis.

20. The wedge type golf club head of claim 19 , wherein said rear portion further comprises at least one hollow chamber and said at least one hollow chamber is filled with a second material having a density greater than a density of a remainder of said wedge type golf club head; and a ratio of said density of said second material to said density of said remainder of said wedge type golf club head is greater than about 2.0.