@paul-69, I won't argue about a dedicated satnav being more robust. But I found my CAT S52 adequately robust. I don't use a case, a rugged device doesn't need one. And I ride a naked bike, so airflow is also adequate. The device shuts down any connector in which water is detected. That happens for the earphone jack while riding in the pooring rain. The USB port has never been a problem, concerning water. But in pooring rain, as a precaution, I simply disconnect the phone from the charger. It can handle more than half a day navigating on it's brightest screen setting. I have used an older phone with waterproof case on my previous bike, an FJR, and found that on hot days my phone would overheat indeed. So, in my view a rugged phone is the most ideal dedicated satnav