Kyocera Echo

The Kyocera Echo (2011) was one of the first dual-screen Android smartphones, released on Sprint in the US. Two 3.5-inch touchscreens hinge together, letting the phone fold flat as a single display, tilt into a laptop-style typing stand, or open fully into a 4.7-inch tablet-style canvas.A small number of apps supported true dual-screen split views, making the Echo a genuinely experimental take on multitasking years before foldables went mainstream. It remains a favorite among collectors interested in early hinge and multi-screen designs.