They are a gas supplier. You can switch to them and National Grid will still bill you and service you. DO NOT give them your account number or they will switch you and then you'll have to contact National Grid to switch back. If you want to consider their business, get their pricing in writing. They claim they are giving you a discounted price but often their price is the same as National Grid or higher. They are VERY persistent and, even after telling them to stop calling me, they still continue to call.