The fundamental element for the Slendertone Abdominal Toning Belt is the medical-grade Gel Pads, which are specifically designed to engage the targeted muscles. These Gel Pads are essential to ensure the user can increase intensities to maximum levels to attain the greatest possible training effect while maintaining their comfort. The length of time the pads will last is dependent on a number of factors including your skin type, frequency of use, how the pads are stored etc. It is recommended that you replace your pads after 20-30 sessions.