Polar Wear Link Hybrid Transmitter Set (X-Small/Small) Ideal accessory for serious athletes and fitness enthusiasts using Polar's line of wireless heart rate monitoring devices Transmitter picks up your hearts signals and transfers that data into compatible Polar training computer Soft, machine washable, antibacterial fabric chest strap adapts to your body shape, bringing full freedom of movement to your training Uses 5kHz and 2.4GHz W.I.N.D. transmission, ensuring heart rate signal is found at all times; transfers heart rate information while swimming Includes limited two-year manufacturer's warranty