Up till now, FiiO had already been in the earphones industry for more than 2 years. During the time, we’ve experienced and learned a lot which made us who we are today. With more and more earphones come out, hereby we would renew the naming rules starting with two letters for any new model later than the F9 PRO as follows: ※ FA: Stands for Balanced Armature earphones; the coming FA7 will be FiiO’s first Quad Balanced Armature IEMs. ※ FH: Stands for Hybrid (Dynamic and Balanced Armature) earphones; such as the FH1 (1D+1BA) and FH5 (1D+3BAs). ※ FD: Stands for Dynamic earphones; the earlier F1, F3 and F5 are dynamic earphones, any future models will name after the FD. ※ FB: Stands for Bluetooth earphones; such as the FB1. ※ FT: Stands for True wireless stereo earphones. ※ FC: Stands for Custom earphones. The naming rules above cover all the current earphones lineup, with which we hope to make it easier for you to know better of our products. We will also keep you updated if there are any future exceptions or new lineups. Best Regards FiiO Electronics Technology Co., Ltd.