AMT is  Ascending Mass Technology - making each shaft progressively heavier by 3-gram increments as golfers move to shorter irons.

AMT Red is the lightest weight and highest trajectory/spin option in the AMT range, maximising speed and launch most by utilising a responsive tip design and maintaining a constant superlight weighting in 4-7 irons, while focusing more on precision and control from 8-iron through wedge.