Chain Key is a single-button input node with hot-swappable mechanical keyboard keys, featuring tactile blue switches and integrated programmable RGB LEDs. Suitable for human-computer interaction, smart home control, and other applications. Chain Key integrates an STM32G031G8U6 core controller, uses the UART serial cascading communication protocol, and can be expanded with more Chain series devices through two HY2.0-4P expansion interfaces to build richer interactive applications. Single-Key input STM32G031G8U6 core controller Hot-swappable blue switch mechanical keyboard keys 2x RGB LEDs Uses UART serial cascading communication protocol 2x HY2.0-4P expansion interfaces, expandable to Chain series devices Specifications MCU: STM32G031G8U6 Input Power: DC 5V Communication Interface: UART Interface Specifications: 2x HY2.0-4P RGB LEDs: 2x WS2812B Power Consumption: 28.24mA Operating Temperature: 0~40°C Color: As Shown Material: plastic Package Contents: 1* Chain Key