Raspberry Pi Zero 2 W offers 2.4GHz 802.11 b/g/n wireless LAN and Bluetooth 4.2, along with support for Bluetooth Low Energy (BLE), and modular compliance certification. The board has a microSD card slot, a CSI-2 camera connector, a USB On-The-Go (OTG) port, and an unpopulated footprint for a HAT-compatible 40-pin GPIO header. It is powered via a micro USB socket. Video output is via a mini HDMI port; composite video output can easily be made available via test points if needed. Sharing the same form factor as the original Raspberry Pi Zero, Raspberry Pi Zero 2 W fits inside most existing Raspberry Pi Zero cases.
Relay 4 Zero is a 4 channel relay shield with 120 V/ 2A AC output and 24 V/2A DC output ratings. Relay 4 Zero is designed for triggering at low voltage levels. Relay 4 Zero provides a solution for controlling low and medium current/voltage devices and makes your projects intelligent. It could be a nice solution for controlling devices that could not be directly controlled by RPi's Digital I/Os. The standardized shield form factor enables a smooth connection with Raspberry Pi and compatibles.
The relay channels 1, 2, 3, and 4 are connected with pin numbers 31, 33, 35, and 37 of the Raspberry Pi respectively. The channels are configurable and can be connected with other pins as well with the help of headers.