Exodus 38:3-7

3And 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.

4And he made for the altar a brasen grate of network under the compass thereof beneath unto the midst of it.

5And he cast four rings for the four ends of the grate of brass, to be places for the staves.

6And he made the staves of shittim wood, and overlaid them with brass.

7And he put the staves into the rings on the sides of the altar, to bear it withal; he made the altar hollow with boards.