Google Glass, a popular smart-glasses product created by the search giant, is expected to make a public debut in 2014. Google Glass was first announced in 2012 and has been continuously improved since then. Google Glass is being used by over a thousand testers, mostly in the U.S. The testers provide feedback and suggest improvements on Google Glass features. Some of the additions that have been made include a voice command prompt for music and navigation. Google launched Glass Development Kit preview to provide access to Explorer Expedition owners with APIs to build apps for accessing hardware. The estimated retail price of Google Glass is $600. Google Glass components cost around $210 and some analysts are expecting the price of Google Glass to drop to around $300.