This is a Garmin chest strap heart rate sensor/monitor. I used it with a cycle computer when riding a road bike. I found it very useful because it measures more accurately than a watch-type heart rate monitor. It can be used with any ANT+ compatible device. There are some minor scratches, but it works without any problems. How about using it for cycling or running? The following is a product description: Garmin heart rate monitor stretch belt, adjustable and comfortable fit. Model: HRM3-SS - Brand: Garmin - Type: Heart Rate Monitor - Material: Stretch material - Size: Adjustable - Features: Heart rate measurement belt