This key fob shell insert is a replacement case for Cadillac CTS and STS models with FCC ID M3N5WY7777A. It is designed to securely hold your original circuit board, battery, and key blade. No programming or cutting is required—just transfer your existing components into the new shell. The durable construction restores the look and feel of your original key. A simple and affordable DIY fix for a damaged or worn key fob case.
