When sourcing 3D screen guards, the material determines the protection level and user experience. High-alumina glass is the premium choice for 3D curved edges due to its superior flexibility and impact resistance. For mid-range markets, standard tempered glass (9H hardness) is common, but ensure it features chemically strengthened edges to prevent chipping. For specialized needs, consider PMMA (Polymethyl Methacrylate) or TPU (Thermoplastic Polyurethane), which offer 'unbreakable' properties and better fit for extreme curved displays.