Fiio f1 in ear earphones a light weight iem designed for fatigue free listening the use of an ultra lightweight polyester diaphragm in its specifically tuned dynamic driver gives the f1 a natural and relaxed tonality that works well with modern pop music since each in ear unit weighs only 24 grams the f1 unlike many other iems youll forget youre even wearing them allowing you to fully enjoy your music japanese copper clad aluminium voice coil a lighter voice coil makes for faster transien