Button layout (standard GM 5- or 6-button configuration):
Top left: Lock (closed padlock)
Top right: Unlock (open padlock)
Center: Remote start (circular arrow)
Lower left: Trunk / rear hatch release (with “x2”)
Lower right: Second trunk / liftgate or power-sliding door style button (with “x2”)
Bottom center: Red panic / alarm button (car + sound-wave icon)
The shell (also called the key fob case or housing) is the outer plastic/metal enclosure that holds:
The circuit board and buttons
The battery (usually CR2032)
The emergency key blade (in models that have one)
It does not include the internal electronics or the transponder chip. Replacement shells are sold separately so you can transfer your existing circuit board into a new housing when the original plastic cracks, buttons wear out, or the look needs refreshing.