Signature Series RCA Shorting Pin Caps (RCA C SP SS) can be used to short out an input RCA. This is desirable on some equipment to lower the noise floor. Some manufacturers ship them with their preamps. With the RCA SP SS the user can decide to either short or not short inputs. Generally outputs prefer not being shorted. Billet brass, nickel plated caps fit over unused female RCA connectors to shield against RFI, EMI, dust and corrosion. Sold in sets of two.