Spinfire V4 Remote is a spare remote control designed for tennis ball machines Spinfire Pro 2. The remote control has been designed to be as small as possible to fit easily into your pocket. The remote control uses a radio frequency of 433Mhz to communicate with the machine. It has been designed to work from a range that easily extends the length of a tennis court. If you are experiencing issues with your remote control, please try replacing the battery (battery CR 2025 3V).