Hamilton Buhl Noise-Cancelling Headphones with Case HamiltonBuhl Hamilton Buhl NC-HBC Noise-Cancelling Headphones with Case - Stereo - Black - Mini-phone - Wired - 32 Ohm - 20 Hz 20 kHz - Over-the-head - Binaural - Circumaural - 5 ft Cable Speaker: 40mm Sensitivity: 105dB 4dB Impedance: 32 Frequency range: 50Hz-20KHz Nominal input (rate power): &lt;50mW Maximum input (power handling capacity): 100mW Active cancellation: Up to 15dB - 20dB Cancellation: between 100Hz  1KHz Battery: One (1) AAA (not included) Cord: 5&#039; Removable Dura-Cord Plugs: 3.5mm TRS with 180 angle (Plugs to Ear Cup End) and 3.5mm TRS with 120 angle (Plugs to Audio Source) Prop 65 Compliant