This won’t work on after market key FOBs as purchased on EBay. These come apart different using the flat blade pocket screwdriver that’s invaluable to the everyday service tech. As the end chrome part comes off, then the entire back comes off. (Caution: the key & spring may release) take photos using your hands to hold the spring, key and front housing together. If it does come apart, place the key in front housing, place tension spring into keys center. New battery installed, place back housing on at the 3:00 position, rotate counter clockwise to feel spring tension. Continue until lined up, snap together and place chrome metal band back on end of both housing. (Note: use pliers to tighten band to tight fit for snapping on) Best of luck with aftermarket Fob. They can’t copy factory design due to copy right issues. Good luck!