Check the listing for details. Etymotic Research ER-4P (ER-4 Micro Pro) Noise Isolating Earphones. Color: Black, Condition: New. Listed at 169.00 USD. Etymotic Research ER-4PThis is the real deal!!!! Original, Unopened!!The ER-4PT microPro In-Ear Stereo Headphones from Etymotic Research provide professional-quality audio in a lightweight and comfortable design ideal for traveling professionals. The headphones use ACCU·Driver balanced armature drivers to produce detailed, realistic audio with better than 86% accuracy from 20 Hz to 16 kHz. The drivers are precision matched and custom tuned, and also deliver extremely high output sensitivity. The headphones come with an industry-exclusive channel-matching compliance graph that's signed by the Etymotic engineer who matched and tuned the drivers.In order to provide the best fit for comfort and noise isolation, the headphones come with 7 different types and sizes of interchangeable eartips. Using the proper eartip creates a seal in the ear that provides up to 98% (35-42 dB) noise isolation, and also reduces the risk of listening to your audio at unsafe levels. In addition to the supplied tips, a separate CUSTOM·FIT option lets you enjoy fully customized eartips.The headphones are designed with lasting durability, and feature a braid-reinforced cable for extremely low microphonic effect. The cable has a gold-plated 3.5mm stereo mini plug and a 1/4" adapter is included for use with a variety of consumer and professional audio devices. Replaceable ACCU·Filters protect the headphone drivers from ear wax and other debris. Other accessories include a filter tool, shirt clip, travel pouch, and storage box.Lightweight and compact design, ideal for travelACCU·Driver balanced armature drivers are precision matched and custom tuned to produce detailed, realistic audio with a high output sensitivity and better than 86% accuracy from 20 Hz to 16 kHzThe headphones include an industry-exclusive channel-matching compliance graph that's signed by the Etymotic engineer who matched and tuned the driversThe headphones come with 7 different types and sizes of interchangeable eartips to provide the best fit for comfort and noise isolationUsing the proper eartip creates a seal in the ear that provides up to 98% (35-42dB) noise isolation, and also reduces the risk of listening to your audio at unsafe levelsIn addition to the supplied tips, a separate CUSTOM·FIT option lets you enjoy fully customized eartipsThe braid-reinforced cable offers lasting durability and extremely low microphonic effectThe cable has a gold-plated 3.5mm stereo mini plug and a 1/4" adapter is included for use with a variety of consumer and professional audio devicesReplaceable ACCU·Filters protect the headphone drivers from ear wax and other debrisOther accessories include a filter tool, shirt clip, travel pouch, and storage box