Callaway Big Bertha irons. Callaway Big Berthas were really the clubs that put Callaway on the irons map. Big faces, plenty of mass around the perimeters of the heads to help keep off-centre hits on target. And yet very light. Completely revolutionary at the time, the principles of a deep cavity, pushing weight to the outside are mirrored in virtually every easy-hitting iron club since. The low centre of gravity help to get the ball airborne more easily with the proper trajectory and spin from almost any turf condition. A Callaway Golf trademark, the S2H2 (Short, straight, hollow, hosel) takes weight from the hosel and transfers it to the hitting area where you need it the most.