Amazon.com: Keyless2Go Replacement for New Keyless Entry Remote Car Key Fob for Select Mazda 6 Vehicles That Use FCC KPU41805 and Model 41805 : Automotive
2016 Mazda 6 Key Fob GP9C-67-5RYB,
Mazda6 Owner's Manual
How to change a dead battery on a Mazda key fob - YouTube