Etymotic invented noise-isolating, in-ear earphones. Etymotic's original insert earphone design, developed for auditory research and medical diagnostics, used balanced armature receivers and established these speakers as the gold standard for high-definition, in-ear earphones. The ER•4 MicroPro series earphones were the first earphones commercialized using this technology and are recognized as the world leader in response accuracy, to which all other earphones are compared. After more than 20 years, these reference-quality earphones are still the choice of serious sound engineers, audiophiles and musicians.

ER•4PT, the newest model in the MicroPro series, is intended for sound engineers and audiophiles in constant motion. ER•4PT combines the acoustic characteristics and features of ER•4P earphones, and comes with extra mobile adapters and accessories for traveling professionals. Also included is an industry-exclusive channel-matching compliance graph, signed by the Etymotic engineer who precision matched and custom tuned the balanced-armature drivers.

The Audiophiliac Review
PC Magazine Review

• Frequency Response: 20 Hz - 16 kHz
• Accuracy Score: 85%
• Transducers: Balance armature
• Noise Isolation: 35-42 dB
• Impedance (@1 kHz): 27 Ohms
• Sensitivity (@1 kHz): SPL at 0.1V: 102 dB
• Maximum Output (SPL): 122 dB
• Cable: 5 ft with 3.5 mm plug
• User Replaceable ACCU•Filters™
• Warranty: 2 years
• CUSTOM•FIT Option