An RNase that has 5'-3' exonuclease activity. May be involved in RNA degradation. Binds 2 Zn(2+) ions per subunit. It is not clear if Zn(2+) or Mg(2+) is physiologically important. Homodimer. Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. Archaeal RNase J subfamily. Truncated N-terminus.