HZRDUS Black Gen 4, the flagship product, and the most advanced HZRDUS yet. Utilizing a new Dual Torsional Design throughout the shaft, HZRDUS Black Gen 4 creates optimized torques and maximum stability while featuring the classic HZRDUS Black profile of stiff butt, x-stiff midsection and stiff tip, suited for an aggressive swinger.Dual Torsional Design is a proprietary process that allows our engineers more freedom when designing a golf shaft—allowing them to dial in stability and desired torques more efficiently, producing a fully optimized golf shaft with regards to player profile.