Quoting_commentary for Exodus 39:22

וַיַּ֛עַשׂ אֶת־מְעִ֥יל הָאֵפֹ֖ד מַעֲשֵׂ֣ה אֹרֵ֑ג כְּלִ֖יל תְּכֵֽלֶת׃

And he made the robe of the ephod of woven work, all of blue;