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The HMEC 300, HMEC 302, HMEC 305,HMEC 305-C, HMEC 306, HMEC 322, HMEC 400
and HMDC 322 are pilot headsets with closed ear protector headphones and NoiseGard™
active noise compensation for use in helicopters, propeller and turboprop aircraft.
Safety tips
• With the NoiseGard™ active noise compensation turned on, typical aircraft sounds
(for example, those from engines, propellers, warning alarms, etc.) may sound
different to you. Before operating any aircraft, make sure that, with NoiseGard™
turned on, you can hear and recognize these sounds. Set the volume to safe levels
that do not interfere with your ability to hear informational sounds and warning
alarms.
• Do not attempt to repair the headset yourself. If problems occur, contact your
Sennheiser agent for assistance.
• Only replace parts of the headset whose replacement is described in this manual.
All other parts of the headset must be replaced by your Sennheiser agent.
• Do not immerse the headset in water! For information on how to clean the headset,
contact your Sennheiser agent.