ESP8266 ESP-01S WiFi Serial Transceiver Module with 1MB Flash for Arduino Feature: SDIO 2.0, SPI, UART 32-pin QFN package Wi-Fi Direct (P2P), soft-AP Integrated TCP/IP protocol stack Integrated TR switch, balun, LNA, power amplifier and matching network Integrated PLLs, regulators, DCXO and power management units +19.5dBm output power in 802.11b mode Power down leakage current of andlt;10uA Integrated low power 32-bit CPU could be used as application processor SDIO 1.1/2.0, SPI, UART STBC, 1×1 MIMO, 2×1 MIMO A-MPDU andamp; A-MSDU aggregation andamp; 0.4ms guard interval Integrated RF switch, balun, 24dBm PA, DCXO, and PMU Integrated RISC processor, on-chip memory and external memory interfaces Integrated MAC/baseband processors Quality of Service management I2S interface for high fidelity audio applications On-chip low-dropout linear regulators for all internal supplies Proprietary spurious-free clock generation architecture The PCB layout has changed for an improvement in WiFi radio performance. Package Including 1pcs ESP8266 ESP-01S WiFi Serial Transceiver Module