Exodus 38:3-7

3And he made all the utensils of the altar, the pots, the shovels, the basins, the forks, and the fire pans. He made all its utensils of bronze.

4And he made for the altar a grating, a network of bronze, under its ledge, extending halfway down.

5He cast four rings on the four corners of the bronze grating as holders for the poles.

6He made the poles of acacia wood and overlaid them with bronze.

7And he put the poles through the rings on the sides of the altar to carry it with them. He made it hollow, with boards.