The Joyroom Helmet-Style Sunshade Bike Phone Holders primarily the Joyroom JR-ZS526 are specifically engineered to block screen glare and prevent smartphone overheating on hot days. Their standout visual feature is a mini "rider helmet" visor that arches over the top of your device.Key Features270° Sunshade Visor: The built-in dual-angle adjustable helmet shields your phone from direct overhead and lateral sunlight, ensuring high visibility for GPS mapping. It also offers light rain protection to keep the screen dry.Overheating Prevention: By keeping direct UV rays off the dark glass of your screen, it reduces thermal buildup, preventing automatic thermal shutdowns and preserving battery health.One-Handed Operation: Designed with a mechanical one-click linkage system, allowing you to instantly mount or release your phone with one hand—a feature highly favored by delivery riders.Rugged Safety & Security: Features a mechanical four-point grip, stainless steel reinforcement, and an integrated anti-loosening lock on the back to keep the phone secured through vibrations and bumps.Wide Compatibility: Fits standard smartphone sizes from 4.7 to 7 inches and accommodates handlebar diameters ranging from 18mm to 35mm.