Mnh complex is a Na(+)Li(+)/H(+) antiporter involved in Na(+) and/or Li(+) excretion and Na(+) resistance. Na(+)/H(+) antiport consumes a transmembrane electrical potential, and is thus inferred to be electrogenic. Does not transport K(+), Ca(2+) or Mg(2+). Forms a heterooligomeric complex that consists of seven subunits: MrpA, MrpB, MrpC, MrpD, MrpE, MrpF and MrpG. Mrp-dependent antiport apparently occurs by a secondary, proton motive force-dependent mechanism, but the similarity of several Mrp proteins to membrane-embedded subunits of energy-coupled NADH dehydrogenase complexes raises the possibility that there is a capacity for electron transport that could provide a primary energy coupling option for Mrp functions. Belongs to the CPA3 antiporters (TC 2.A.63) subunit B family.