Not showing up in inspector using [System.Serializable]

public Button testButtons;

 [System.Serializable]
    public class ButtonClass {
    
    	public RectTransform rectTrans;
    	public Text buttonText;
    	public Image buttonBody;
    	public UnityEvent onHighlightCall;
    	public UnityEvent onInvokeCall;
    
    }

For some reason “testButtons” is not showing up in the inspector.
What to do?

testButtons is type Button but your class is ButtonClass