3.How is the RF signal quality of the FW1? Is the connection stable?

The FW1 adopts high-performance LDS Radium Vulture antennas and was precisely tuned. So its RF performance and consistency is better than the low-cost ceramic antenna and FPC antenna. It is stable and reliable in normal use.
However, due to the complexity of Bluetooth frequency band and environment, the connection stability might be influenced when using in complex environments. So it is suggested to put the mobile phone as close as possible to the master earbud.