5V-24V relays are shipped without an external case because the main purpose of them is being integrated into another electronic device such as a gate opener.
But when used as a standalone relay, this protective case is a useful extension to the relay. Both 5V-24 WiFi, WiFi+RF and Zigbee+RF versions of the relay are compatible with this box.
Note: 1-gang relay's switch button on the relay board is short, so you will need a pin to push them for a manual on/off switch or pairing mode.
