Most people are getting upset saying that these dont cancell out sound. Its true they dont they are called open air over the head,headphones. You can pretty much hear everything outside which is good for me becuase if you dont want to cancel people out or hear what someone is saying these wil lbe very good and helpful for you here are the specs and what the manufater says The UR40 delivers digital quality sound in an ultra-lightweight design for listeners on-the-go. The UR40 features dynamic elements for a wide frequency response from 15-22,000 Hz. A 2 mil. titanium coating on its diaphragms increases the rigidity of the elements, minimizing mechanical distortion and ensuring exceedingly accurate sound reproduction. Computer-optimized neodymium iron boron rare earth magnet structures enable the UR40 to deliver greater volume, even with low-voltage portable devices. Oxygen-free copper voice coils improve signal transmission and conduction for cleaner, clearer sound. With its hybrid design, the UR40 combines the best of closed-style and open-style headphones. Closed leatherette earcushions form a light seal around the ears, enhancing bass frequencies. Screened earcups provide an open, hear-through sound that lets listeners stay in touch with the world around them. The result is a full frequency, clean sound that turns any recording into a "live" performance. At just over six ounces the UR40 wears comfortably even after hours of continuous listening. The airy mesh sling provides soft breathable support, ideal for those with touch-sensitive scalps. An adjustable headband accommodates all head shapes and sizes for maximum comfort. When not in use, the resilient, lightweight frame folds into a compact configuration that's protective, easy to carry and convenient to store. Perfect for travel, the UR40 includes a straight dual-entry eight foot cord. A gold-flashed 3.5mm (1/8") plug, L-shaped to minimize cord stress is included. The UR40 will delight listeners seeking heavyweight sound in a comfortable lightweight package. Built to last, the UR40 is covered under Koss' Limited Lifetime Warranty - the only warranty of its kind in the stereophone industry.