Polar RS300X Heart Rate Monitor - new in box, never worn, will need new battery About this item Wristband Size : 8.5 “ . NOTE - Measurements taken from the LAST HOLE to the END OF RUBBER next to buckle (not from end to end). Easy-to-use heart rate monitor guides you to train at the right intensity Includes H1 heart rate sensor chest strap for continuous, accurate heart rate. Uses coded transmission to avoid cross-talk with other heart rate monitors nearby. Built-in Fitness test helps you can track and monitor your fitness improvement Displays accurate calories burned and records last 16 training sessions and your last 16 weeks of training