If I could have only one IEM and put all my eggs in one basket, I‘d be hard pressed to find a more stunning flagship than the Erlkönig and would probably save up to get what could very well be considered a real endgame universal IEM. Build quality is nothing short of perfect and fit and isolation are as good as it gets for a universal. The Erlkönig is technically flawless with fantastic resolution, a pitch black background which provides fantastic note contrast and class leading soundstage but more importantly every of its technical abilities is at the service of a very musical and smooth tuning that you can tweak to your preference. What more could you wish for?