Previous page Legendary Sound In 1970 Koss set the standard for full-size professional headphones with the Pro/4AA. High-Fidelity Audio Pro/4AA features oversized elements for an exceptionally dynamic 10-25,000Hz frequency response. Superior Noise Isolation Adjustable slide bars provide a snug fit, critical for monitoring and sealing out unwanted noise. Built to Last Ultra durable design ensues Pro/4AA can withstand frequent use and demanding environments. Legendary Colorway Pro/4AA was the first Koss Headphone to use the iconic Koss Rhythm Beige colorway. Next page 1 Pro/4AA 2 Legendary Sound 3 Noise Isolating 4 Ultra Durable 5 Rhythm Beige Superior Noise Isolation In 1970 Pro/4AA set the standard for full-size professional headphones with impressive noise isolating capabilities. The Sound of Koss Pro/4AA were regarded as the first dynamic headphones to deliver true full frequency and high-fidelity performance at 10-25,000Hz. Coiled Cord A convenient and compact 8 foot coiled cord with 3.5mm plug and included 6.3 mm (1/4 inches) adapter provides a tangle free listening experience. Adjustable Headband Enjoy a comfortable listening experience with a durable steel and integrated adjustable and padded headband. Legendary Headphone. Legendary Colorway. John C. Koss In 1958 founder John C. Koss changed the way we all listen to music when he invented the world's first SP/3 Stereophone. In 1970 Koss would set the standard for full-size professional headphones with the introduction of the Pro/4AA. Rhythm Beige The iconic Koss Rhythm Beige colorway can be found on many legendary Koss Headphones like Porta Pro Limited Edition, KPH30i and KPH40 Utility - but it was first introduced in 1970 with the release of the Pro/4AA. Frequency Response 10-25,000- Hz Impedance 250 Ohms SPL 95dB SPL/1mW Plug 3.5mm with 6.3mm adapter Cord Coiled, Single Entry, 8ft Headband Adjustable Released 1970 Included Pro/4AA, 6.3mm adapter More Products From Koss Pro/4AA Add to Cart Porta Pro Add to Cart Porta Pro Limited Edition Add to Cart Porta Pro Utility Add to Cart KPKH40 Utility Add to Cart KPH30i Buying Options KSC75 Add to Cart Customer Reviews 4.4 out of 5 stars 893 4.6 out of 5 stars 16,606 4.4 out of 5 stars 1,990 3.9 out of 5 stars 203 4.4 out of 5 stars 1,080 4.4 out of 5 stars 3,486 4.4 out of 5 stars 8,397 Price $79.99$79.99 $39.99$39.99 $59.99$59.99 $49.99$49.99 $39.99$39.99 $21.99$21.99 $19.59$19.59 Headphone Type Over Ear On Ear On Ear On Ear On Ear On Ear Ear Clip Connection 3.5mm (includes 6.3mm adapter) 3.5mm 3.5mm Utility Series Utility Series 3.5mm 3.5mm Utility Series — — — 3.5mm, USB-C & Lightning 3.5mm, USB-C & Lightning — — Audio Controls — — In-Line Remote Utility Cord Remote Utility Cord Remote In-Line Remote — Microphone — — In-Line Remote Utility Cord Remote Utility Cord Remote In-Line Remote — Noise Isolating Yes — — — — — — Adjustable Headband Yes Yes Yes Yes Yes Yes — Collapsible — Yes Yes Yes — — — Carrying Case/Pouch — Carrying Pouch Hardshell Case Carrying Pouch — — —