A solid start, the Polar RS100 has all the essential features for running - a good choice for your first monitor, it will motivate you and keep you going. It has an oversized 3 row display, woth a backlight. It is water resistant to 50metres and has a very useful low battery indicator. Measures your heart rate combined with flexible timing features. Automatically sets your heart rate aerobic zones depending on how hard you want to train. Shows you how many calories and the percentage of fat you?ve burned. Calculate your time spent on each exercise, how well you?ve kept to certain sport zones and how many calories you?ve burned. Records up to 99 lap/splits for every training session so you can work to improve on your best time and monitor your heart rate over time.