Harbinger AB Carver Pro - BlackThe Harbinger Ab Carver Pro is an ab wheel with a patented design that improves the effectiveness of ab exercises and helps to engage and strengthen muscles in the back, chest, arms, and core. Unlike traditional ab wheels, the Ab Carver Pro uses a unique carbon steel spring mechanism that provides resistance as users roll out and assistance as they roll back, engaging muscles more thoroughly. While most ab rollers feature flat wheels that only allow