Transmembrane complex that mediates resistance to copper and silver by cation efflux directly from the cell using the proton-motive force. Spans the inner membrane, periplasm, and outer membrane. Primarily activated under anaerobic conditions by CusR and CusS but also expressed under extreme copper stress, in aerobic growth. [ http://www.ncbi.nlm.nih.gov/pubmed/23122209 ]