David Clark H9940 Wireless Behind-the-Head Dual Ear Headset - 40991G-01

The David Clark H9940 (40991G-01) Wireless Headset Microphone is a dual ear, behind the head communication headset designed for the Series 9900 Wireless Intercom System and David Clark wireless belt stations. Built as a marine grade version of David Clark’s legacy noise attenuating headset platform, it is engineered for demanding environments where teams need robust, reliable wireless communications around high noise equipment. In aviation, it is widely used for ramp operations, aircraft maintenance coordination, and other ground support workflows where mobility matters. It is also a strong fit for marine operations, fire rescue, and industrial facilities that require secure wireless intercom performance.

• Supports wireless intercom communications through Series 9900 wireless belt station systems.
• Designed for use in extreme noise environments up to 125 dB with a noise cancelling dynamic microphone.
• Provides passive noise attenuation to help protect hearing and improve communication intelligibility.
• Marine grade hardware supports corrosion resistance in harsh environments.

Key Features

• M2 dynamic microphone with water resistant protection and strong noise cancelling performance.
• Hybrid hinged wire and flex microphone boom for precise placement, with reversible hardware for left or right positioning.
• Dual dynamic earphones with titanium nitride drivers and stainless steel retainers.
• Dual water tight volume controls for independent left and right adjustment.
• 6 ft extended coiled cord with military grade 7 pin belt station connector (MAP-57-50).
• Comfort gel ear seals and an adjustable overhead support assembly designed for long shifts.

H9940 (40991G-01) Specifications

• Weight: 16.3 oz (462 g)
• Certified NRR: 23 dB (3rd party)
• Passive Noise Attenuation Rating: 23 dB
• Communication Cord: 6 ft coil with MAP-57-50 connector
• Ear Impedance: 35 ohm plus or minus 10 percent at 1 kHz
• Ear Frequency Response: 20 Hz to 20 kHz
• Microphone Principle: Dynamic
• Microphone Impedance: 5 ohm nominal
• Microphone Frequency Response: 150 Hz to 8 kHz

For aviation ground support teams and other high noise industries that need secure wireless intercom communications with dependable hearing protection, the David Clark H9940 (40991G-01) delivers rugged performance, strong transmit clarity, and comfort built for long duty cycles.