Soft strap: package includes 2 packs black heart rate chest straps, convenient for your to replace the old one, great for sports and activities where a wrist unit would be difficult to use Simple strap: this black strap has good elasticity and adjustable length, soft and comfortable to wear, easy to clean and won't corrode, very useful strap for outdoor exercise Adjustable strap: heart rate monitor strap with adjustable belt designed, it can extend from 25-37.4 inch, please check you needed size before you purchase Material: the part of the strap mainly adopts soft fabric and is adjustable to your size, button style fasteners design, which provides the comfort and security needed when exercising Compatible with: heart rate chest strap compatible with Polar, Garmin, Suunto and more brand, Please note: this is a compatible spare part and the manufacturers' names and part numbers have been mentioned above for reference purposes only