All Sigtronics headsets and intercoms are specifically designed for high-noise environments and are RFI and EMI immune, giving you clear, interference-free transmission even in fabric or composite aircraft or in use with handheld radios.True High-Fidelity Stereo. Sigtronics exclusive infinite baffle system delivers sound the way you want it. Our stereo speakers are specifically designed to deliver a wider frequency range than mono versions for better quality sound. Sigtronics stereo headsets also offer an integrated stereo / mono switch and dual volume controls for the ultimate in quality, comfort and sound reproduction for the discriminating pilot. Stereo headsets are also recommended for those with unequal hearing abilities in each ear.