ORIGINAL ESP32 ESP-32 ESP32-WROOM-32D ESP32D IoT Module Chip

Both modules have ESP32-D0WD chip on board of a smaller footprint than ESP32-D0WD installed in ESP32-WROOM-32. By default the module has 4MB flash and may be also ordered with custom flash size of 8 or 16MB, see Espressif Products Ordering Information. Version “D” has a MIFA antenna. Version “U” has just an U.FL / IPEX antenna connector. That makes it 6.3 mm shorter comparing to “D”, and also the smallest representative of the whole WROOM / WROVER family of modules.