Review on Enhanced Performance: Keyecu Red Flip Remote Key with 315MHz 4D63 80 BIT Chip for Ford Mercury Lincoln FCC: CWTWB1U212, CWTWB1U331, GQ43VT11T, CWTWB1U345 by Tyler Cash

Now I know the manufacturer of this key fob says it shouldn't work. But it's like a championship. I can confirm it works great on a 2006 Ford F250 6.0 Diesel. People might say it can't be programmed. Not true. Everyone forgets to first hold the door open and press the unlock button on the driver's door and then close it. You then turn the ignition on 8 times in ten seconds (between off and work) while landing at work. The truck will confirm that you have programmed the key fobs by clicking on the door locks. Then lock each key fob you want to pair with the truck. Turn off the key and you're done. Now when I wanted to see if they were going to "marry" I used the factory key. As you can see you need to trim the ignition cover for the new keys to work. (See image.) Totally worth the money to combine the keychain into one key. Note however. The F250 doesn't have a trunk, so don't expect this button to do anything! common sense people. But they work.