Brushing alone is not enough! The Waterpik Cordless Freedom Water Flosser is a great solution when you want the convenience of cordless water flossing. Battery operated and portable, it's perfect for use in smaller bathrooms or for travel. The Cordless Freedom includes 3 AA batteries. These batteries will need to be replaced when a significant decrease in pressure is noticed. Assuming daily use, batteries will likely need to be replaced every 1 to 2 months, depending on quality of batteries.