The 2008 Smart Fortwo remote key must be cut and programmed before it will work for your vehicle. Cutting and programming can be performed at a local automotive locksmith or dealership. There are no onboard programming instructions available for 2008 Smart Fortwo This Remote Key comes with a new battery Installed and is tested for functionality before sending. This Remote head key comes with 4 buttons and if you look on the back of the unit, you may see some of these numbers: KR55WK45144 – 267T-5WK45144 CMII ID: 2007DJ1481 – 315 Mhz . Use these numbers to confirm that your Remote head key will match this product and that it will work for your vehicle.