Etymotic ER2 SE/XR Noise-Isolating Earphones (Open Box) 4.4mm male a proprietary 9mm rare-earth magnet

a proprietary 9mm rare-earth magnet subwoofer with the ability to deliver extreme output

when the earbud is stored in the charging case and the lid is closed

COAXIAL STRUCTURE HIGH-PURITY IMPORTED SINGLE CRYSTAL COPPER WIRE

Featuring the magnesium housing and grill design of the LCDi4

Etymotic ER2 SE/XR Noise-Isolating Earphones (Open Box) 4.4mm male a proprietary 9mm rare-earth magnetWhich ER2 is right for you? Both ER2 models, the ER2SE and ER2XR, use the same low impedance dynamic drivers. That means they are easy to drive, and no amplifier is required. The only difference between the 2 models is the tuning of the lower (bass) frequencies. The Studio Edition ER2SE is tuned to have a flat frequency response. The eXtended Response ER2XR is tuned to have an emphasized bass, adding 1 2dB to the mid bass and 3 4dB to the sub bass.