How long can the batteries last? The Hair Coach uses 2 AA batteries. The batteries lasts up to 6 months with daily brushing (one 30 second per day). Related articles Can I sync the Hair Coach with the Nokia Health Mate app? Which devices are compatible with the Hair Coach? Does the Hair Coach come in multiple colors? Can I sync my Nokia Thermo with the Nokia Health Mate app? What is the Hair Coach and what does it measure? Didn't find what you need? Here's how to get in touch. Contact us Call us Customer Support ID (this number allows secure and easy account verification when communicating with our support team by phone): To view your Customer Support ID, please log in by clicking on 'login' at the top of the page. Hours of Operation: North America: Monday through Friday, 9 am - 10 pm Eastern Time (6 am - 7 pm Pacific Time).If you are unable to reach us by phone, please use the ‘Send us an email’ button to send an email instead.Disclaimer:Free call and assistance. Calls placed from outside of these locations may be subject to long distance fees. All phone calls may be monitored and/or recorded for quality purposes.