GR D2是小型、超声波收发通讯设备，可用于2个以上潜水员或水面站之间的通讯。Buddy Phone D2由数字信号处理，声音清晰。
Ø Nominal Range: 50 to 500 meters depending on sea conditi*** & noise levels.
Ø Tran***ission Type: Ultrasound using upper single sideband (USB)
Ø Tran***it Output Power: 1/2 Watt PEP
Ø Standard Frequency: Freq. A (Channel 1): 32.768 kHz USB,
Freq. B (Channel 4): 31.250 kHz LSB
Ø Audio Bandwidth: 300 to 3,000 Hz
Ø Automatic Gain Control: Greater than 80 dB
Ø Earphone: Ceramic
Ø Microphone: ME-16R Hot-Mic (Dynamic) or Super Mic (Standard)(Ceramic)
Ø Transducer: Ceramic cylinder
Ø Battery Type: Alkaline 9V or Ultralife lithium 9V or 9V Li-polymer rechargeable. Batteries not included
Ø Maximum Operating Depth: 130 feet in sea water (fsw)