CARDAS AUDIO Noise dust Stopper Protective RCA Caps cover plugs. Shield and protects against unwanted Noise and RF, EMI interference (4 Pieces) 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 4 pieces Cardas Signature Series RCA C SS Caps