Features Premium metal build: nearly every aspect of the N400 is built with a sturdy matte-metal finish, from the charging case to the buds themselves. Ambient Noise Cancelling: not the best ANC that I?ve heard, but hey, it exists. IPX7 rating: personally IPX4 is already enough for a TWS IEM so IPX7 is a nice overkill bonus for those who want to, I don?t know, shower with music or something. Decently sized charging case: not the smallest thing out there, but it fits in my pocket and doesn?t feel like I shoved a powerbank in there. In terms of these four metrics that I?ve highlighted, most TWS buds out there (even the ?premium? ones) tend to hit one or two but never the whole deal. Apple?s AirPod Pro and Sennheiser?s Momentum True Wireless get the closest to the clean sweep, though comes up short on the IPX rating and the somewhat flimsy plastic build (for the APP, at least).