The 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 for rolling straight out and back, the Ab Carver Pro features a wide, spherical wheel that helps users engage all ab muscles, including obliques, by pivoting to the right and left. This helps to strengthen deep core muscles that stabilize the pelvis and spine. The Ab Carver Pro also features padded, angled, ergonomic hand grips that maximize engagement of arm muscles while remaining comfortable and stable. The Ab Carver Pro includes kneepads and a 1-year manufacturer’s warranty.