Mozilla unveiled three Firefox OS reference platforms: a 4.5-inch Flame phone and 7- and 10-inch tablets, and showed a prototype of a $25 Firefox OS phone. At Mobile World Congress in Barcelona, Mozilla announced the first formal reference smartphone for its Linux-based Firefox OS == the self-branded Firefox OS Flame phone — as well as the first developer tablets. The latter comprise an already tipped 7-inch Via ???Vixen??? tablet, and a 10-inch ???InFocus??? tablet from Foxconn.