The world is so full of noise that it can be difficult to find the quiet you need to concentrate or to enjoy your favourite music. When you need to block out the sounds of the world, you need a pair of Noise Cancelling Headphones. Monoprice Noise Cancelling Headphones have been designed to provide superior noise cancellation, leaving a quiet, empty soundstage in which to experience your favourite music. Additionally, they can be used without any musical or audio content when what you need most of all is peace and quiet. The Active Noise Reduction circuity will eliminate almost all external sounds, giving you the quiet you need to think and concentrate.The ANR circuitry is powered by a single AAA battery (included), which can power it for up to 50 hours. The headphones can also be used in passive mode, without the ANR circuitry enabled, which gives you excellent musical reproduction, while allowing you to hear some of the environment around you. The headphones come with 55" audio cable with an inline microphone and control module, a 58 inches standard audio cable with a 90-degree connector on one end, a headphone/microphone splitter for use with PCs, a 3.5 mm to 1/4 inches plug adapter and airline plug adapter. They are packaged in a luxury "hardshell" zippered nylon storage case, which includes a nylon mesh internal pocket for the included cables and accessories. The carry case includes a D-ring, which can be used to attach a strap (not included) or to secure it to a backpack.