§ 654 Peremptory challenge defined.

Both the prosecution and the defense get to remove a certain number of potential jurors without giving any reason. This is called a peremptory challenge. Either side can use it, and they can even do it out loud in court without writing anything down.

The key point is that no explanation is needed. If a lawyer wants to strike a juror using this type of challenge, the judge must excuse that juror automatically. The lawyer doesn't have to prove the juror is biased or unfit. This gives both sides some control over who ends up on the jury, based on their own judgment or instincts about a potential juror, even if they can't point to a specific legal reason.