I would like to thank Spider Cable for choosing me and generously sending out a review sample of their premiere product .   Specification: driver size: 12.5 mm diameter driver nozzle size: 5.5 mm impedance: 18 ohm (not listed so I pulled out my multimeter) weird impedance number might be in house produce driver(sorry typo on 48 ohm corrected) the housing seem to be made of aluminium coated with plastic(best guess due to weight and feel but might be pure plastic) ipod volume controls and mic there is a rear bass...