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.
Platinum Prices Per Ounce, Gram & Kilo. To the right are live platinum spot prices per troy ounce, gram, and kilogram. You can also see 24-hour trends for each weight.Please scroll down for a full, interactive platinum price chart, and also view our popular platinum bullion product categories below:latinum prices are typically quoted in U.S. dollars (USD) per troy ounce. As with most commodities, platinum is usually quoted in USD, but prices may be converted to any local currency.