Garmin Approach X40, GPS Golf Band and Activity Tracker with Heart Rate Monitoring, Black GPS receiver - high-sensitivity GPS acquires satellites quickly to Show distance to greens, Hazards and doglegs -even under Tree cover Auto shot - round analyzer measures shot distances with auto-recording for post-round analysis on your Garmin connect account 24/7 Heart rate monitoring - Elevate wrist Heart rate technology allows you to track your Heart rate all day and night - Activity Tracking Accuracy (go to Garmin. com/at accuracy) Activity Tracking - reminds you to stay active on or off the course with move bar alerts ; Display size: 1. 00 x 0. 42 Inches Battery life - rechargeable battery: up to 5 days in activity mode; up to 10 hours in GPS mode Regular: 5. 4-7. 6 (136-192 mm) circumference X-large: 7. 1"-8. 8" (180-224 mm) circumference