Features: Energy efficient 3.97inch E paper Link display module maintains crisped content without power for HAT integration with SPI compatibility for multiple development boards. Features shifting chip for 3.3V/5Vcompatibility and wide viewing, requiring not with backlight while preserving last screen data during power interruptions. Designed for developers, industrial engineers, and makers low power visualization for intelligent device prototyping. Perfect for digital shelf labels, warehouse inventory trackers, factory equipment monitors, and energy efficient instrumentation requiring persistent display updates. Streamlines prototyping easy for HAT standardization, enabling rapid expansion through SPI communication and industrial grade plastic housing durability. Specifications: Working voltages: bare screen version: 3.3Vmodule version: 3.3V/5V. Display color: black and white Display size: about 86.40x51.84mm/3.4x2.04in Module Size: about 99.5x60mm/3.92x2.36in Version: Screen version / Module board Package Includes: 1PC 3.97inch E Paper Screen note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.