The PreSonus HD9 is a pair of professional-quality monitoring headphones, which deliver loud, clear, and clean audio, while minimizing listening fatigue. The HD9 sports 45mm dynamic, neodymium drivers with high-power handling (900mW per channel into 40 Ohms) and an extended frequency response from 10 Hz to 26 kHz for accurate bass response and precision mixing. The closed-back, circumaural design keeps the sound inside the ear cups for isolation while tracking, while the adjustable headband and comfy earpads are designed for long listening sessions. The single-sided cable is 10' long to provide plenty of slack, giving you freedom to move about your workstation or console. The 1/8" stereo plug connects to a variety of professional audio devices. The PreSonus HD9 ships with a gold-plated 1/8" to 1/4" adapter and a storage bag.