Cardas XLR Female Caps
These XLR Caps fit over unused male XLR output connectors in your system to eliminate EMI and RF noise absorption.
These caps do not short the outputs.
Cardas XLR Caps completely cover the connector with a solid shield of nickel and brass to prevent both EMI and RFI from entering the chassis.
This is a more elegant and probably more effective solution than either shorting plugs or wrapping the plug in aluminum foil. The Female XLR caps also protect the XLR inputs from dust and corrosion.