Designed for power walking and aerobic exercise, the Alvita Optimized (HJ-321) counts your aerobic steps separately from normal walking steps, as well as the distance, calories burned, and time you've traveled, giving you more information about your overall activity level. It accurately counts every step, using Omron's tri-axis technology. The HJ-321 pedometer also allows for 7 day memory to track all of your activity over the course of a week and has four separate activity modes to provide and even more accurate description of movement. Just wear it on your hip or place it in your bag or pocket.