Review on Pair of KeylessOption Chipped Key Transponder Replacements for Ford 4C H72 Ignition by Jonah Riggle

Although these said they work with my 2004 F150 - not program - even though I had two original keys. They were listed as working with 40 or 80 bit Ford security systems. When they didn't work, I ordered two different pairs of dongles from Revain, which said they only work with 40-bit systems. They're easy to program on the first try - and now, a few weeks later, they're working perfectly. If you have an older Ford that uses a 40-bit security system - BUY 40-BIT KEYS! Don't take chances with them. They may work fine for 80-bit systems or other 40-bit systems, but they will not work with the 2004 F150! I believe the original 40-bit keys have a single "H" stamped into the key's shank.