Tesla has never provided them for some reason. I bought a couple of these in desired colors for my wife and I - will update on if they work well. The quality seems good (I already have them and have played around with it) and you get a couple options for the connector to hold the keys. The enclosure actually is screwed in place around the fob so no chance the fob slides out. It’s a good design as long as it doesn’t interfere with the signal.
View attachment 810518
ISDORE Premium Key Fob Cover for Tesla Model X - Aircraft Aluminum Flip Key Protection Case with Leather Keychain -
Amazon.com