Comfortable chest strap for heart rate measurement compatible with Polar, , products.The smart of soft fabrics and adaptive electrodes make it extremely sensitive toBeing an indispensable part of heart rate monitor, it will detect and send your real-time heart rate to the smart phone accurately.The most popular heart rate belt in the world easy to use yet is very durable. Utilizes the snap attachment method.Color: BlackThis light garment is compatible with all heart rate sensors(ANT+, Bluetooth 4.0, 5.3K).With the chest strap based on , it can be attached to your skin closely.your hearts electrical signals, so the heart rate sensor can pick up your heart rate quicker and more accurately.Material: Silica gel + fiberBelt length: 90-130cm / 35.4-51.2inPackage Included:5 x Adjustable Elastic StrapOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.