This Earphone

Buy.com has the Acoustic Research ARE05 in-Ear Noise Isolating Headphones for $20 with free shipping. Bass Level Isolating Soft Silicon technology further reduces outside noise for a precise and rich bass response.

Product description from Buy.com:

ACOUSTIC RESEARCH ARE05 In-Ear Noise Isolating Headphones

Features Detailed, accurate sound across full frequency range–20 Hz-20 kHz High-performance 16mm neodymium drivers Custom-fit, !
in-ear design with small, medium & large changeable ear pieces Natural noise isolation Lightweight, sleek construction stays securely in place on the go Low-profile connector fits almost any 3.5mm jack, including the Apple? iPhone?

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