It's all but impossible to open a review of iPhone-compatible headphones without commenting on the quality of the headphones you get in the box with every iPhone. They're rubbish. That's not a unique observation either, but it's surprising that a company that prides itself on being a "premium" brand such as Apple continues to keep shipping out such ordinary headphones by the million. Still, if nothing else, it keeps the third-party premium headphone manufacturers in business. That's exactly what the a-Jays Four offers; a replacement set of headphones specifically targeted at iPhone users.
We've been largely impressed with the Jays line of headphones in the past, and the best way to describe the a-Jays Four is that they superficially resemble the a-Jays /Two/Three headphones in the use of a flat ribbon cable, multiple silicone ear buds to the preference of your fit and a hard plastic case for storage. The difference on the surface of the A-Jays Four is the inclusion of an in-line remote 15cm down the cable for the right ear bud. The buttons on the remote aren't labelled, although they are concave for volume and convex for speaker/play/skip controls.
While they physically resemble the a-Jays One line, the a-Jays Four has slightly higher specifications, with a claimed sensitivity of 96dB @ 1kHz, 16 Ohm impedance and a frequency response of 20-21000Hz. This puts them in the middle of the claimed specifications of the a-Jays Two and Three headsets, at a slight price premium to both.
Given that price premium, it's surprising to note that you don't get any of the accessories that typify the higher numbers in the Jays range. There's no stereo splitter. There's no inflight adapter. These are pitched and designed solely for iPhone users (and potentially iPod Touch/Mac users), and so the accessory count is low.