Cardas XLR FEMALE Caps are used to fit over unused MALE XLR sockets to eliminate EMI and RF noise absorption. They are non shorting and completely cover the XLR's opening with a solid shield of nickel and brass to prevent EMI and RFI from entering the chassis through the dielectric. This noise can create havoc with digital processing and software. Cardas caps also protect XLR's from dust and corrosion. They feature the Signature Series Nautilus logo engraved onto top surface of the cover. Sold in sets of two. Male units also available.