The ophanim or ofanim (Heb. "wheels" אוֹפַנִּים ’ōphannīm) refer to the wheels seen in Ezekiel's vision of the chariot, the Book of Enoch (61:10, 71:7) portray them as a class of celestial beings who (along with the Cherubim and Seraphim) never sleep, but guard the throne of God.
An excerpt from the Bible, Ezekiel 1:15-21:
"As I looked at the living creatures, I saw a wheel on the ground beside each creature with its four faces. This was the appearance and structure of the wheels: They sparkled like topaz, and all four looked alike. Each appeared to be made like a wheel intersecting a wheel. As they moved, they would go in any one of the four directions the creatures faced; the wheels did ...