Exodus 38:4

And he made the altar of burnt offering of shittim wood: five cubits was the length thereof, and five cubits the breadth thereof; it was foursquare; and three cubits the height thereof.

And he made the horns thereof on the four corners of it; the horns thereof were of the same: and he overlaid it with brass.

And he made all the vessels of the altar, the pots, and the shovels, and the basons, and the fleshhooks, and the firepans: all the vessels thereof made he of brass.

And he cast four rings for the four ends of the grate of brass, to be places for the staves.