What is the best product to protect hair and scalp during sun exposure?

I will be going on vacation in a few days and will be in the sun daily. I have thing hair, due to AGA and deal with TE from time to time. I wear hats alot of the time, but I want to know what hair/scalp sun protector product might be best to use when I do not have a hat. There are many products claiming to be dual body&hair sunscreen, or hair/scalp sprays with SPF but not sure if they're effective. I am hoping you may be able to provide me with the best product/option or alternative. Thank you!

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