Features: brand new and high quality Communication protocol support UART SPI 12C CAN 12S SDIO HRS4H-S-DC5V relay: maximum switching voltage AC 250V for DC 28V It can be connected to the T-U2T USB to serial downloader, or it can be directly powered by TypeC USB On-board functions: 8 relays, optocoupler isolation, 16 expansion IOs Since the motherboard does not have a download chip programmed, this product needs to use the T-U2T automatic downloader for uploading programs. Support T-U2T downloader, 8 blue relay working indicators Specifications: Item：ESP32 T-Replay MCU: ESP32-WROVER-E Flash: 4MB PS Memory: 8MB Maximum switching current: 15A External power supply voltage input range: DC12V-24V Wireless Protocol: WI-FI: 802.11b/g/n Bluetooth-compatible: V4.2 BR/EDR/BLE Size:approx 17X8.5X1.8cm/6.69x3.35x0.71in Type: H561/ H561 Q320 (Optional) Package Includes: 1 Set x ESP32 T-Replay note: Since the motherboard does not have a download chip programmed, this product needs to use the T-U2T automatic downloader for uploading programs. Due to the problems of lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-1cm error due to the manual measurment.