Use official ones, sice 23u is slightly curved along the edges. It will be a plastic Membrane one but woll cover almost whold display area and some official screen protectors peovide anto reflecting properties.
I have the UV screen glass from the day one of the purchase, and it's working fine with my device. I saw some videos on YouTube that are opposed this glass, but I never felt any discomfort in touch or fingerprint or anything.
