All battery purchases are refundable (within 30 days) only if it is new and still in resellable condition. If you have altered it in any form, it is not refundable. If the item is defective, it will be replaced at my cost. Please read the product's specification and dimension to make sure it fits your plane. Of course, you can always email me with questions and I would be happy to answer them. Please note that the use of battery in the radio control models are beyond manufacturers' specs. As such, no warranty are provided. You should always seek out fellow modelers who are more experience to assist you in your purchasing.