NEI-4000 series is SP-OFC (Silver Plated Oxygen Free Copper) audio interconnect cables.
Neotech NEI-4001 interconnect cable has quad balanced structure. Conductor (SP-OFC) are insulated with Foamed Polyethylene, and wrapped together by a double screen - AL-Mylar foil and Tinned OFC braided shielding, to reject RF & EM Interference.
Neotech NEI-4002 interconnect cable is a balanced design item with Polyethylene insulation. The double screen shield consists of AL-Mylar foil & Tinned OFC braided shielding to reject RF & EM Interference.