2.5 mm stereo connection for use with WIFI handset, PDAs or cell phones. Dielectric construction. Dual receivers provide a crisp audio response. SED® lightweight noise attenuating earcups provide consistent, comfortable protection and superior sound quality. Unique combination of an adjustable behind-the-head steel tension band and two fully adjustable velcro straps provide day long wearing comfort and a secure fit even under a hardhat or helmet. Replaceable soft foam ear pads ensure the best comfort possible and a longer life span of the headset.