Oregon Scientific SE138-G Strapless Heart Rate Monitor SE138 is a strapless ECG heart rate monitor, which allows users to be free from the trouble & discomfort of bringing & wearing a chest belt. Just by placing your fingers on the watch for few seconds, it will measure your heart rate. Packed with other functions like clock, alarm, stopwatch & calorie consumption calculation, SE138 in a simple design, makes it a perfect match for many kinds of fashion trends.