Chipset:ESPRESSIF-WROVER-B 240MHz Xtensa single-/dual-core 32-bit LX6 microprocessorFLASH: QSPI flash 4MB / PSRAM 8MBSRAM: 520 kB SRAMButton:reset indicator lamp: redUSB to TTL: CP2104Modular interface: UART.SPI.SDIO.I2C.LED PWM.TV PWM.I2S.IRGPIO.capacitor touch sensor..DACLNA pre-amplifierOn-board clock: 40MHz crystal oscillator Working voltage: 2.7V-3.6VWorking current: about 30mASleep current: 10uAWorking temperature range: -40 degree ~ +85 degree Supply Specifications Supply: USB 5V/1ACharging current: 500mABattery: 3.7V lithium batteryWi-Fi Standard: FCC/-RED/IC/TELEC/KCC/SRRC/NCC(esp32 chip)Protocol: 802.11 b/g(802.11n, to150Mbps)A-MPDU and A- MSDU polymerization,support 0.4S Protection intervalFrequency range:2.4GHz~2.5GHz(2400M~2483.5M)Transmit : 22dBmCommunication distance: 300mBluetoothProtocol: meet bluetooth v4.2BR/EDR and standardRadio frequency: with -97dBm sensitivity NZIF receiver Class-1,Class-2&Class-3 emitter Audio frequency: CVSD& audio frequencySoftware specificationWi-Fi Mode: Station/SoftAP/SoftAP+Station/P2PSecurity mechanism: WPA/WPA2/WPA2-Enterprise/WPSEncryption Type : //ECC/SHAFirmware upgrade: UART download/OTA(Through network/ to download and write firmware)Software Development: Support cloud server development /SDK for user firmware developmentNetworking protocol: IPv4.IPv6../UDP/HTTP//MQTTColour:blackMaterial: PCBSize:39 x 30mmPackage Contents:1 * development boardOnly the above package content, other products are not included.Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.