Everyone knows the problem: you buy a screen protector to protect your phone, but what you often get is a new problem. Installing it without bubbles or dust? For most people, it's almost impossible. Once it's finally stuck on, it turns out to be crooked. Or your fingerprint sensor suddenly stops working. With cheap kits using UV glue, the glue can even get into your speaker, and when removing it, you sometimes pull off more than you'd like.

The everyday experience is also often disappointing. Screen protectors that react slowly to your touch. Edges that come loose as soon as you use a case. An oleophobic layer that disappears after a few weeks, making your screen look greasy. Or privacy screens that protect against onlookers, but also reduce your own clarity. And meanwhile, the market is littered with buzzwords like "9H hardness" and "unbreakable glass" – without anyone explaining exactly what that means.