
WinBridge Portable Neck Lanyard Clip Microphone Audio 3.5mm Compatible with all WinBridge Speech Amplifiers Foil Screen The basic screen is the most common. It consists of a single layer of aluminum mylar wrapped around pairs of conductors. This provides basic protection against EMI/RFI interference. Although the foil shield covers up to 100% of the cable pairs, it does not offer the best protection for all frequencies. http://www.jmkfilters.com/faq.htm#radio_frequency_interference