Screen protection is the category for our different types of screen protection. As a starting point, there are tow types of screen protection, plastic and glass.
Plastic screen protection is a thin plastic film that is glued to the phone or tablet. Plastic screen protection provides limited protection as you can still scratch through.
The other type which is glass protection is much harder than plastic. Over the plast couple of years the development has gone strong and glass protection has become thinner but still more robust. You measure the hardness of glass protection on a scale of 1-10 where 10 is the most hard material such as diamond. The latest glass screen protection has a hardness of 9. That is, they are significantly more resistant to scratches than ordinary glass.
Besides the hardness it is also important that the screen protector can withstand dirt and grease. In general use, greasy fingers etc. will be deposited on the screen. Adding an "Oleophobic coating" ensures that fingerprints are not deposited as easily on screen and also ensures that the screen is easy and clean.
Keep in mind that the screen protectors are phone specific and you shouls therefore find the one that fits your phone exactly. Also, keep in mind that it is important to protect the rest of the phone. You can do that with a cover or bag that you find in this category.