Our 12V 300ma 7 Watt or 500ma 10 Watt Regulated UL Listed Power Supplies (Transformers) are normally used for security cameras (ours included). Specially designed to be well suited for work with 12V DC cameras that draw MA ratings less than either of these. However if your camera's specs use within '50' of the 300ma limit, then we recommend choosing the next option up - the 500ma Power supply. Please call if you have any questions that need answers. Power supply cable is 6 ft. long.