Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earspeakers, earphones or, colloquially, cans. Circumaural and supra-aural headphones use a band over the top of the head to hold the speakers in place. The other type, known as earbuds or earpieces consist of individual units that plug into the user's ear canal. In the context of telecommunication, a headset is a combination of headphone and microphone.
Osmium is usually sold as a minimum 99.9% pure powder. Like other precious metals, it is measured by troy weight and by grams. Its price in 2012 was about $400 per troy ounce (or about $13,000 per kilogram), depending on the quantity and its supplier.
As of 25 July 2011 Uranium costs US $ 51.50per US pound or US $113 per kilogram of natural uranium in â¦ the form of the unrefined uranium oxide (U3O8). How much does uranium cost on the black market per ounce? Usually, trade is preferred, with testicles bringing the most in trade. A blowjob will get you around 5 pounds of uranium.