8チャンネル5Vリレーシールドモジュール

It do it job as should be.

Works perfectly

Work as expected !

The description says these relays can be directly controlled by an Arduino. In fact, you need to use a transistor for each relay as the input pins need to be switched to ground to activate the relays . As long as you recognize this limitation, this is a great product. Also, use a separate 5V power supply. It is easy to overload the Arduino UNO 5V source.