Exodus 38:4

38:4 He made a grating for the altar, a network of bronze under its ledge, halfway up from the bottom.

Exodus 27:4

27:4 You are to make a grating ¹  for it, a network of bronze, and you are to make on the network four bronze rings on its four corners.

[27:4]  ¹ tn The noun מִכְבָּר (mikhbar) means “a grating”; it is related to the word that means a “sieve.” This formed a vertical support for the ledge, resting on the ground and supporting its outer edge (S. R. Driver, Exodus, 292).