There's nothing quite as frustrating as a deep gouge on your new phone's screen. Still, it can be hard to bring yourself to put on some stupid-looking screen protector. Unless it's as tough as this one that we attacked with a hammer. And a drill.

Sir Lancelot's Armor's "The Holy Grail" is a lot impressive than its aggressively groan-worthy name. We saw this sheet of tempered glass defend against scratches from knives, razors, drills, and corkscrews first-hand, winding up none worse for the wear. It's punishment no reasonable phone should ever go through, unless you've got a jackhammer on your keyring.

It can also help protect from impacts, or at least some of them. This won't save you from a dreaded corner-drop, but it could help you out if something falls on your phone, even if the glass has to shatter in the meantime. We brought the hammer down on it—literally—a few times, with a solid but not totally ludicrous smack, and it held up admirably. When it finally did crack, the phone itself remained totally intact. Meanwhile, the folks at King 5 News were even able to get it to help defend against a (pretty poorly aimed) gunshot. If or when it does break, it has a lifetime guarantee; all you have to do is ask for a new one.

Of course it's not all magic; The Holy Grail has a few downsides too. In direct sunlight, it's got a matrix of dots that's painfully visible, and once I took it off my Nexus 5 to adjust it, I had a hard time getting it to go back on. Also it's pretty expensive at $30 for phone versions and $50 for tablets. But the cost of having a divot on your screen is one you have to pay in infinite frustration with every glance you take at your favorite gadget. How much are you willing to bet that you're not a total butterfingers? [Sir Lancealot's Armor]