I just bought this charging capsule, and I wanted to share my experience with trying to get an answer to a simple question. I recently bought the Fitness Earbuds, but my charging case was broken in an accident. I'm trying to find a replacement and seeing this charging capsule, I'm going to try it out, but beforehand, I tried several times to reach out by email or the "ask a question" to find out if my Fitness Earbuds will work with this device. Still, to this day, I haven't heard back after a week of reaching out. I'm taking a shot and hopefully it works, but I really wish Raycon could be better with customer service, as their Contact Us is just only article pages about generic topics, or I wish on this page it could have a list of every earbud that it is compatible with not just the one line that it doesn't work with the Work Earbuds Classic. Even if I get it and it doesn't work be forewarned when returning it within 30 days you only get a "credit" for their site which also really sucks too because if Raycon can't supply me with a replacement charging case for the Fitness earbuds I might have to try eBay or a third party site which kind of grosses me out. If I get the case and it does work I'll come back and write another review but until then, 3-stars.