Life tenure is all we're talking about here. It's all that exists in federal courts of general jurisdiction. Every federal district, circuit, and supreme court judge appointed by the President and confirmed by the Senate is life tenure.

Magistrates, who operate only on the district court level (not in the appellate courts or supreme court), are not Article III judges. They're appointed by the actual Article III judges without input from the President or Senate, and they can handle cases only by the consent of both parties, and their rulings are appealable to an actual Article III district court judge.