The original Pi-oT™ IoT Module brings the Raspberry Pi 3 or 4 up to par with 5 high quality relays and 8 analog inputs.
The ESP Module™ provides the Espressif ESP32 a home in high demanding applications with 4 relays and an assortment of IO's.
The Pi-oT 2™ brings the Raspberry Pi 4 a host of IO's, including DI, DO, AI, and RS485.