For the most effective workout, and maximum calories burned. the zone trainer 3.0 allows for continuous heart rate monitoring to accurately measure the effectiveness of your workouts. A stylish design with silicone strap is designed for the ultimate in both comfort and fashion, and a fabric chest strap can wirelessly transmit continuous heart rate data to your easy-to- read watch display. now, tracking your workout has never been easier or more pleasant to look at. Brand: Oregon Scientific Model SE331M Dimensions: 1.8 x 4.4 x 6.1 Battery Type: CR2 Color: Black Waterproof: No Recommend Use: Heart-monitoring, burned calorie tracker Features: Tap on lens for toggling through your favorite modes. Sleek design: smaller and less bulky with lie flat design. Comfort band: soft silicone strap with aeration for maximum comfort. Easy-to-read display: better quality LCD with larger characters. Digital time and calendar.