Chain DualKey is a programmable dual-button input development board equipped with an ESP32-S3FN8 main control chip. The front integrates two hot-swappable blue switch mechanical keyboard buttons and two programmable RGB LEDs, providing excellent interactive feedback. Built-in 350mAh lithium battery, combined with low-power design, offers good battery life. Factory-installed Chain macro keyboard firmware, supports USB/BLE connection, simulating HID input devices. After startup, the device can connect to the device's access point (AP) hotspot. Through the built-in web page, HID function mapping for the local machine or extended nodes can be configured to meet various control needs. This development board features an expandable design, equipped with two HY2.0-4P expansion interfaces, supporting horizontal expansion and connection to other sensor devices. Leveraging the ESP32-S3's built-in USB-OTG peripheral functionality, it is suitable for smart home applications, keyboard peripherals, macro keyboards, and other scenarios. Features: ESP32-S3FN8 main control chip Built-in 350mAh lithium battery 2 programmable RGB LEDs 2 hot-swappable blue switch keys Expandable design -compatible hole design on the back Lanyard design Applications: Smart home control Macro keyboard Keyboard peripherals Specifications: SoC: ESP32-S3FN8 @ Dual-core XtensaLx7 processor, up to 240MHz Flash: 8MB Input Power: USB: DC 5V Battery: 350mAh Lithium Battery RGB LEDs: 2 x WS2812B Operating Temperature: 0~40℃ Standby Current: Power Off Mode (VBAT): DC 4.2V@8.97uA Deep Sleep Mode (VBAT): DC 4.2V@107.64uA USB 5V Power Supply (without battery): DC 5V@41.7mA Color: As Shown Material: plastic Package Contents: 1* Programmable Dual-Button Input Development Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.