We are intially looking for 500 sets with additional quantities as and when required.
We are willing to look at different brands as long as the spec is the same:
Soyntec Netsound 240 Headphones
Frequency range: 20 - 20 Khz.
Sensitivity: 108 dB +/- 3 dB at 1 Khz.
Impedance: 16 Ohm.
Cable length: 1,2 m.
Maximun power input: 60 mW.
Jack: 3.5 mm.
We would also like some sort of protective case or cover to go with each set.