Detect dead pixels, stuck pixels, and LCD defects on any screen – phones, tablets, monitors, and laptops. A free, browser-based tool that cycles through solid colors (red, green, blue, white, black) in fullscreen mode. No download, no signup, works on any device with a web browser. Perfect for: - Testing new monitor purchases before the return window - Checking used/refurbished displays - Quick diagnosis when you suspect screen defects