Callaway Hawkeye Titanium. Callaway Hawkeye Titanium irons were the top of the range Callaway product when they were launched. Callaway's nearest current equivalent - the Fusions - use the same titanium/tungsten principle to achieve usability. The heads are made of titanium (which is incredibly light - half the weight of steel) while in the cavity is a hidden weight port which runs behind the impact area and is home to the Tungsten Weight Matrix, which contains tungsten (very heavy metal) spheres. This weighting system allows for a very low centre of gravity. The weight is placed in the optimum position for each iron; low in long irons, higher in the short irons. Aimed essentially at higher handicappers, Callaway's Hawkeye Titanium irons are a very easy club to hit.