Your Apple Watch lets you live free and stay connected, so you want to feel confident wearing it everywhere, even on the most extreme adventures. Glass ZTR4 is ZAGG's strongest screen protection. It's fortified with graphene - one of the strongest materials on Earth, and it has a rugged aluminum frame for added strength and style. XTR4 protection also has a blue light filter, antireflective technology, and a super smooth surface. XTR4 is premium protection from the number 1 name in screen protection.