ESP-WROOM-02 SMD Modules Espressif Systems ESP-WROOM-02 SMD Modules integrate the ESP8266EX Wi-Fi SoC and provides excellent RF performance. The ESP-WROOM-02U module offers optimized RF performance compared to ESP-WROOM-02 and incorporates a U.FL connector. The Espressif Systems ESP-WROOM-02U module features dimensions of 18mm x 14.3mm x 3.2mm, while the same for ESP-WROOM-02 is 18mm x 20mm x 3mm.