A screen protector is an additional sheet of material—commonly polyurethane or glass that can be attached to the screen of an electronic device and protect it against physical damage. Screen protectors are made of either plastics, such as polyethylene terephthalate (PET) or thermoplastic polyurethane (TPU), or of tempered glass similar to the original tablet or smartphone screens they are meant to protect. Plastic screen protectors cost less than glass and are thinner, around 0.1 mm (0.004 in) thick, compared to 0.3 to 0.5 mm (0.012 to 0.020 in) for glass. At the same price, glass will resist scratches better than plastic, and feel more like the device’s screen, though higher priced plastic protectors may be better than the cheapest tempered glass models. A glass protector is superior to its alternatives in every way. It has better light transmittance, making for a clearer display. It’s anti-reflective and glare reducing. It has oleophobic coating, which heavily reduces fingerprints. It has the smooth feel of actual glass under your fingertips. Unlike Gorilla Glass, it resists sand scratches, making it the only viable option for beachgoers.