Cobra LTDx Ladies Irons The revolutionary design of the LTDx women's irons starts at the core. The construction features a multi-layer PWR-COR weighting system that lowers CG, and promotes maximum flexion of the body, sole and face for peak ball speed and distance. PWR-COR Technology A multi-layer PWR-COR weighting system features a steel core bar that is suspended within a polymer injected casing.