Callaway Steelhead X-16. The Steelhead X-16 irons have a wider topline than the their predecessors - the Callaway X-14s. Featuring Callaway's patented VFT (Variable Thickness Technology) which enabled Callaway's designers to alter the thickness and raise or lower the centre of gravity for optimum trajectory with each iron in the set, the Steelhead X-16s also incorporate the Callaway 'Notch' weighting system which moves weight to the perimeter - the result is a club which not only plays easily - but looks like it plays easily. Utilising Callaway's 360-degree undercut channel which helps straighten off-centre shots, each iron has a low centre of gravity for getting the ball airborne quickly. A nice looking club with a soft satin finish.