Sennheiser HD400 Instructions For Use Manual page 43

HMEC 400 NoiseGard™ headset
The HMEC 400 differs from the HMEC 300 in the following features:
• Stylish silver design
• Leatherette ear cushions
• Headband padding can be buttoned
HMDC 322 NoiseGard™ headset
The HMDC 322 differs from the HMEC 300 in the following features:
• No Mono/Stereo switch
• Coiled cable
• M-87/AIC dynamic microphone and low impedance headphones
• Connection of headphones and microphone via U-174/U jack plug to a low impedance
interface in the helicopter
117