Exodus 37:1-3

And Bezaleel made the ark of shittim wood: two cubits and a half was the length of it, and a cubit and a half the breadth of it, and a cubit and a half the height of it: and he overlaid it with pure gold within and without, and made a crown of gold to it round about. And he cast for it four rings of gold, to be set by the four corners of it; even two rings upon the one side of it, and two rings upon the other side of it.