Exodus 38:3-7

3And he made all the vessels of the altar, the pots, and the shovels, and the basins, the flesh-hooks, and the firepans: all the vessels thereof made he of brass. 4And he made for the altar a grating of network of brass, under the ledge round it beneath, reaching halfway up. 5And he cast four rings for the four ends of the grating of brass, to be places for the staves. 6And he made the staves of acacia wood, and overlaid them with brass. 7And he put the staves into the rings on the sides of the altar, wherewith to bear it; he made it hollow with planks.