While most cars are sold with remote keys already programmed to the vehicle, there are instances where the remote may need to be reprogrammed or replaced with another key. One of the most common reasons remotes will need to be programmed is simply because they become unprogrammed accidentally. If the owner does not have a spare can use blank keys or reuse your old key. That's why you need Key Cleaner Tool to wipe out all memory of your old key and prepare it to programming. The exact wipe instructions for the key will depend on the make and model of the vehicle. Key Cleaner Tool Read/Write PCF79XX Chip to unlock remotes, actually erase memory and prepare car key to reuse. However, to program the remote control again, you need to use a key programmer. Fitment:For PCF7941 PCF7952 PCF7953 Compatibility is for reference only. Please Compare The Part Number With Your One Before Purchasing! Note: If you are not professional for technology, please don't buy this product. Installation guide not included, we strongly recommend you seek professional installation. Please check as much as possible to make sure the item is what you need. Tips:The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use. Colour:As Shown Material:PCB Package Contents: 1 * Key Eraser v1.5 Key Cleaner Tool Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.