The art hp 1 personal in ear monitor amplifier is a compact headphone amplifier powered by 2 x aa batteries included ideal for live performers'. '.strtoupper('r')obust and portable the hp 1 is the perfect companion for any musician providing high output amplification with variable volume control'. '.strtoupper('w')hen performing hearing what the crowd hears can make or break your performance'. '.strtoupper('w')ith the hp 1 you dont have to worry about your sound as this powerful headphone amplifier will capture every detail of your performance allowing you to monitor your sound as you perform'. '.strtoupper('n')ot only is it great for use with in ear monitors the hp 1 can also be used as a headphone amplifier'. '.strtoupper('w')ith up to 40 hours of battery life from 2x aa batteries youre always prepared to perform with the hp 1'. '.strtoupper('t')he 1 4 inch xlr combo input jack features a locking design that ensures your headphones iems stay connected whilst you perform'. '.strtoupper('u')tilising high quality components the hp 1 provides a reliable and efficient way to amplify your iems headphones complete with a sturdy belt clip you can attach to your clothing for hands free operation.