It's the first and only soft fabric transmitter, the WL combines superior Polar technology with a new fabric design. -Compatible with all Polar heart rate monitors, the Wearlink has a user replaceable battery and coded transmission eliminating interference from other HRMs. The Wearlink is backed by the Polar standard 2 year maintenance free warranty and the battery, a 6 month warranty. -Please note; uncoded receivers will not receive the benefit of the coding