Highly Accurate - 98 to 99% - Yamax Power Walker EX-510
3D Accelerometer Sensor filter In order to recognize actual walking activity, 3D sensor has 11 steps filter.If you move less than 11 steps and take about 5 seconds no-motion break, previous 11 or less steps will not be counted. This device can store up to 30 days of memory data and 30 weeks of accumulated weekly data. Each of number of steps, calorie, fat burn, distance walked and activity time are stored in memory at 2:00 am after midnight every day. Accumulated Week Data will be stored from Monday to Sunday up to 30 weeks.