Fender FXA2 Pro In-Ear Monitors Overview :The FXA2s feature custom 9.25mm precision rare-earth driver with Groove-tuned port that offers a crisp treble and a tight, punchy low end (6Hz- 23kHz) that’s perfect for bassists and drummers. The tone is crystal clear and highly sensitive, resulting in distortion free sound with plenty of headroom. This ensures you get an optimum listening experience at all times.The Perfect fitThe FXA2 monitoring headphones use 3D-printed digital hybrid technology (DHT) to create the perfect fit for your ears. After scanning thousands of different ears, they came up with a custom design that will fit 95% of ears like it was custom made for you. This is combined with SureSeal tips, where you can choose the perfect fit to fit comfortably in your ears ears so that the audio gets fed directly where it’s needed. The tight fit offers 18dB of noise reduction. This not only isolates your ears from unwanted background noise but also protects your hearing from the consistent High SPL of a live environment. An invaluable line of defence for a musician!The monitors feature a 16-ohm @1khz impedance which essentially means that you get the option to plug into both professional live audio equipment as well as plugging into your mp3 player and getting a decent volume.