Exodus 38:3-7

3He made all the altar’s utensils of bronze—its pots, shovels, sprinkling bowls, meat forks, and firepans. 4He made a grate of bronze mesh for the altar under its ledge, halfway up from the bottom.

5At the four corners of the bronze grate he cast four rings as holders for the poles. 6And he made the poles of acacia wood and overlaid them with bronze. 7Then he inserted the poles into the rings on the sides of the altar for carrying it. He made the altar with boards so that it was hollow.