It's a reworked version of the Sony Xba-h3. If Jant71 could chime in, it would help. And pardon my earlier comments guys. I am still bitter about sony's earlier products. It'll go away for sure. I still have hope that they can improve on their original mistakes with their old lineups with this new earphone series. The A3 should be a great update to the H3s. The Z5 should blow competition away if they have done their homework, which I highly believe. Let's hope for the best.