Feature: 1.Designed to work as a ANT+, Bluetooth armband replacement is perfectly compatible with most heart rate monitor and sensor , , , , and more brand heart rate monitor armband. 2. armband replacement width is 20 mm, length is 400mm/15.7 inch. Wearing size between 7.5 inch-13 inch(19-33cm). The comfortable, stretchy, and adjustable band can be worn on the forearm, biceps, or triceps. 3. replacement Strap is , breathable, sweatproof and lightweight. Easy to install and remove, use as simply as the arm band.The band's Material is tough and make you can' feel it. 4.The arm band is made of material. Fully washable. 5.Nylon Buckle design a snug fit especially suitable for running, swimming, yoga, cycling, various outdoor sports and home workout. Material: color: Black Length: 400mm Width: 20mm Package Contents: 2 Pcs Replacement Band Only the above package content, other products are not included. Note: Light reflection 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.