Polar Loop Activity Tracker Wristband Size : 9  . NOTE - Measurements taken from the LAST HOLE to the END OF RUBBER next to buckle (not from end to end). *Loop is from end to end prior to cutting. Wristband Size : 9  . NOTE - Measurements taken from the LAST HOLE to the END OF RUBBER next to buckle (not from end to end). *Loop is from end to end prior to cutting. Worn on your wrist, tracks your activity 24/7 and provides guidance and motivation to reach your activity goals Shows daily activity, calories burned, steps taken, time of day and activity feedback on 85 LED display; Plus monitors sleep patterns Automatically syncs to free Polar Flow app and training community via Bluetooth Smart. For best results use updated Flow app version 1.0.1. Refer the user manual for product help and support. Custom fit bracelet is waterproof for swimming and has rechargeable battery; Battery life 5 days in continuous use Provides accurate heart rate with Polar H6 or H7 Bluetooth Smart heart rate sensor accessory (not included, sold separately)