Geeksphone's new Keon smartphone was unveiled at this year's Mobile World Congress in Barcelona.
The new handset uses Mozilla's Firefox OS and features an orange casing, giving it a theme that properly represents the software.
The Keon features a 3.5-inch display with 480 x 320 pixel resolution, making it a fairly low-end smartphone aimed at customers not looking to shell out too much money for a new device.
It will be priced in between $100 and $150 and will be the first Firefox OS smartphone available to buy. It will go on sale in the next few weeks worldwide.
The Keon runs the latest version of Firefox OS, which is an open-source software based on HTML 5 and is not demanding on hardware. The device features a 1GHz processor so complex systems such as Android 4.1, JellyBean would not work well on it.
Firefox OS resembles both iOS and Android in different ways.
It is similar to Android as it comes with multiple home screens. It also resembles iOS with its large grid of application icons. CNET describes it as "quite neat and fairly attractive." However, apps will end up being a major problem for the OS, as developers will not want to create three different versions for iOS, Android, and Firefox. Mozilla hopes that the open nature of HTML 5 will allow developers to easily tune their apps to work on the software.
Firefox OS will also come pre-installed on some high-end devices. Sony is expected to introduce a device that uses the software sometime next year. This was revealed in an event held by Sony and a Spanish carrier known as Telefonica.
Other companies such as Alcatel, LG, ZTE and Huawei have expressed their interest in Mozilla's OS and also may release smartphones running the software in the future.