Cardas protective RCA Caps helps to shield and block your system from unwanted noise and RF, RFI, EMI emissions Prevents and stop dust & dirt from building up in unused open RCA connectors Connect RCA Caps to unused connectors in audio systems, cables and instruments to eliminate RFI, EMI interference Machined into one solid metal shape for exact fit Includes 12 pieces Cardas Signature Series RCA C SS Caps Cardas Audio's SRCA Signature Series is the company's ultimate male RCA plug. It features non-magnetic, eutectic brass, and rhodium over silver plate. The brass cover is gold plated. It has a spring-loaded tensioner on the outer ring and a 9.5mm cable opening.