My car came with a sports key (surf key, wet key) that is waterproof and can be used to open and start the car. This is useful when at the beach. The ordinary key stays in the car and is disabled when the sports key is used to lock the car.
BUT… the Volvo sports key has a non-replaceable battery that only lasts 2 to 3 years (whether or not it is regularly used). There is no obvious warning when the battery is getting low, other than becoming less reliable unlocking the car. Fortunately the last time the sports key failed to open the car my partner was nearby with the normal key.
This made me realise that relying on a battery-operated car key in remote areas is risky. Some car keys have a manual key that can be used to open the car and, once inside, the key should be able to start the car with NFC. Otherwise it is best to at least carry a spare battery (if replaceable).
Don’t get me started on the cost of replacement sports keys!
