What is the timebox for the sprint Review?

The timebox for the Sprint Review is four hours for a one-month Sprint, as stated in [4]: “The Sprint Review is held at the end of the Sprint to inspect the Increment and adapt the Product Backlog if needed. During the event, the Scrum Team and stakeholders review what was accomplished in the Sprint and what has changed in their environment. Based on this information, attendees collaborate on what to do next. The Product Owner explains what Product Backlog items have been “Done” and what has not been “Done”; additionally, they discuss any changes to scope or budget or potential value. The entire group then collaborates on what to do next, so that the Sprint Review provides valuable input to subsequent Sprint Planning. The Sprint Review is a working session and attendees should inspect based on facts. A Sprint Review is held at the end of every Sprint for a maximum duration of four hours for a one-month Sprint.”