Sennheiser HDI 434

The HDI 434 (also written HDI434) was a wireless hi-fi stereo headphone manufactured by the Sennheiser Corporation. Here are some of its features and specifications.

• Battery life: 100-hours (approx)
• Frequency Response: 20 Hz to 20 kHz
• Max SPL: 105 dB
• Carrier frequencies: 95 kHz (left channel), 250 kHz (right channel)
• Mass: 380 g
• Powering: 9 V battery