SP32 is far superior to Arduino UNO. That means it has all the features you need to create your projects, ESP32 can perform as a complete standalone system or as a slave device to a host MCU, reducing communication stack overhead on the main application processor. ESP32 can interface with other systems to provide Wi-Fi and Bluetooth functionality through its SPI / SDIO or I2C / UART interfaces

ESP32 is the name of the chip that was developed by Espressif Systems. This provides Wi-Fi (and in some models) dual-mode Bluetooth connectivity to embedded devices. While ESP32 is technically just the chip, modules and development boards that contain this chip are often also referred to as “ESP32” by the manufacturer

ESP32-WROOM-32U is a powerful, generic Wi-Fi + Bluetooth + Bluetooth LE MCU module that targets a wide variety of applications, ranging from low-power sensor networks to the most demanding tasks, such as voice encoding, and music streaming, and MP3 decoding.
ESP32-WROOM-32U is different from ESP32-WROOM-32D in that ESP32-WROOM-32U integrates a connector to connect an external antenna

When the ESP32 is set as a Wi-Fi station, it can connect to other networks (like your router). In this scenario, the router assigns a unique IP address to your ESP board. You can communicate with the ESP using other devices (stations) that are also connected to the same network by referring to the ESP unique IP address

ESP32U is a low-footprint and entry-level development board that is part of the ESP32 series. This board has a rich peripheral set. The built-in ESP32 pinout is optimized for hassle-free prototyping.

Applications:

1. Smart industrial devices, including Programmable Logic Controllers (PLCs)
2. Smart medical devices, including wearable health monitors.
3. Smart energy devices, including HVAC and thermostats.
4. Smart security devices, including surveillance cameras and smart locks
5. All IOT Projects

Wi-Fi Station

Features: 

1. ESP32-WROOM-32U can be programmed in different programming environments
2. On board Wi-Fi + Bluetooth + Bluetooth LE MCU connectivity
3. Use in IoT Projects
4. Small and compact Dev module
5. You can connect with a router or your devices
6. Easy to learn & use
7. Rapid Prototyping
8. Flexible and Feature-Rich
9. Breadboard-Friendly

Specifications: 

1. Antenna: external antenna connector (which needs to be connected to an external antenna)
2. Product: IoT Development Board
3. Model: ESP32-WROOM-32U
4. The CPU clock frequency: 80 MHz to 240 MHz
5. Tensilica Xtensa LX6 dual core microprocessor
6. Bluetooth Range: 100 m
7. Wi-fi: 802.11 b/g/n (802.11n up to 150 Mbps)
8. Voltage: 3.6V
9. Current: 500mA
10. ROM: 448 KB ROM
11. SRAM: 520 KB SRAM
12. On board: Wi-Fi + Bluetooth + Bluetooth LE MCU
13. Operating Temperature:–40 °C ~ +85 °C

Packages Includes: 

1 x ESP32-WROOM-32U IoT Development Board Module