Great product! But leave the battery cap off between uses... [SEP] Sonicare are great products, as my dentist has noticed.<br /><br />The only problem with this great replaceable battery version is that the batteries didn't last for more than a week or two. Until I discovered that removing the battery cap between uses made the batteries last 2-3x as long.<br /><br />I can only guess that there is a small constant current drain on the batteries. Removing the cap disconnects them and stops that constant 24-hour-a-day drain. Then they last fine. I use NiMH rechargeables.