SONY MDR-5a (1980) Guardians of the Galaxy ■ Price 8,000 yen ■ Model Open Air Dynamic type ■ Diaphragm 23 mm dome shape ■ Impedance 32 Ω ■ Playback frequency band 20 - 22,000 Hz ■ Allowable input 100 mW ■ Sensitivity 98 dB / mW ■ Code 3m Weight 50 g (not