Plantronics H31CD is an improved version of the original H31.  Plantronics H31CD boost the incoming audio level to make listening easier in noisy environments. Plantronics H31CD (part# 43674-01) is recommended for dispatch operators, air traffic controllers, military, stock exchange, 911 dispatch operators. The H31CD StarSet requires the Plantronics SHS1890 Adapter to connect to most Dispatch Consoles. If using it with a telephone, you need a Plantronics M22 Vista amplifier or bottom cable between the headset and the telephone. call for compatibility if you're unsure. 

Key Features:

• Receiver Impedance (ohms, at 1 kHz): 600 ± 150
• Source Drive Impedance (ohms): 600
• 1kHz sensitivity (dBPa/V, ±4 dB): 20.5
• Flexible Eartube style
• Quick Disconnect feature
• Ideal for noisy environments, featuring a complete 6-Size eartip kit.
• Ideal for those who need a comfortable, convenient headset for noisy environments.
• The ultra-lightweight, StarSet headset rests comfortably behind the ear.
• Innovative design
• All day comfort
• Easy on, easy off

Old Poly part # 43674-01

New HP part # 8K780AA#AC3

<= This headset has a Quick Disconnect end.

Also see Plantronics H31CD datasheet

Important Note: This headset requires the Plantronics M22 Vista amplifier or bottom cable between the headset and the telephone. call for assistance.

Optional Accessories for the Plantronics H31CD:

Plantronics Voice Tubes Mirage Headsets-Clear (3-Pack)

Plantronics Voice Tubes Mirage Headsets-Color (6-Pack)

Plantronics H31/H31N Versa Tip

Plantronics H31 / H31N Versa Earpiece Kit (6 sizes)

Plantronics H31/H41 Eyeglasses Clip Kit

Plantronics CA10CD Push-to-Talk Cordless Amplifier 

Plantronics CA12CD PTT Adapter 

Plantronics SHS1890-10 6-wire Push-to-Talk Amplifier 

Plantronics SHS1890-15 6-wire Push-to-Talk Amplifier 

Plantronics SHS1892-10 4-wire Push-to-Talk Amplifier 

Plantronics SHS1892-15 4-wire Push-to-Talk Amplifier 

*Important Note on Returns: Due to the manufactures policy, this is a special order item.  All Sales are FINAL.  It's not returnable, not refundable under any circumstance.  If it's defective, Plantronics will replace it for you under warranty