Cardas RCA C SS Protection Caps 

For the audiophile who has nearly everything. These are part of a range of cumulative tweaks that take good setups to great. These billet brass nickel-plated caps have the Cardas nautilus logo and are meant to fit over unused female RCA connectors to shield against RFI, EMI, dust, and corrosion. 

Note, these are not shorting caps, so they are safe to use on inputs and outputs.