For safety reasons, I have never been one to run outside with earphones in both ears. For years I have cut off one of the cords on most of my earphones so I could run with music or podcasts in one ear, and have the other ear free to hear traffic, other runners, cyclists, etc. You know how when you listen to music and you will hear something different in both ears? Well by cutting off a cord, I was missing out on some of my music! In 2011 Far End Gear introduced a single earbud that combined both stereo channels, solving this issue.
In 2012 he took it a step further by introducing the Brite Bud.
Developed with the nocturnal athlete and outdoorsman in mind, Brite Buds™ Reflective Cord Earbuds employ the same inter-locking plaiting process used in high-grade parachute cord. Weaving water-resistant fibers with glass bead retro-reflective threading has resulted in the creation of the first line of reflective earphones specifically designed for strength and increased visibility during nighttime activity.
I've been using the One Good Earphone and now the Brite Bud since late 2011 and consider them an important part of my training gear. I even use them often while not running. The sound quality is excellent and I never feel like I'm missing anything by only having one earbud in.
You can purchase the Brite Bud as a single earphone or a double. The package includes three different sized rubber tips, to customize fit. I have yet to have it fall out, even while performing <400m repeats on a track.
Far End Gear also has the other products. The Short Buds have a 15" cord. Perfect if you have your music player hooked to your sleeve or cap and want to avoid extra cord. The One Good Earphones are a non reflective single sided earphone.