Compatible with all Polar heart rate sensors, the Pro Chest Strap securely carries your sensor in a comfortable design that won't slip, no matter how intense the workout is. Slip-preventing silicone dots grip this strap in place without irritation, and an adjustable buckle locks down the fit with security every time you put it on. Plus Polar put extra interference-preventing electrodes on the strap to make it extremely sensitive to your heart's electrical signals, providing maximum precision for heart rate readings and eliminating any possible interference.