Ms. Miller: The main problem that happens with the UPS is the batteries need to be replaced, just like a car battery. There are still led acid batteries, so we recommend that you change them every three to five years. We have a serial number and we know where each one of our UPS’s is, who we sold it to, the date, where it went, and the application it was used for. We are proactive and every three years we will remind our customers to change their batteries. Our customers trust us and our products and they know it is going to work. Our units have a feature where you can do a battery test on it and it will let them know the life of the battery also.