Swivel phone

A swivel phone is composed of multiple—usually two—segments, which swivel past each other about a sagittal axis (most of the time). Use of the swiveling form factor has similar goals to that of the slider, but this form factor is less widely used. Samples are, LG U900 + 960 + V9000, Motorola Flipout + V70 + V80, Nokia 7370, Siemens SK65, Samsung Juke + Samsung SGH-X830, and Sony Ericsson S700i + W600. The LG Wing implemented this feature into a slate design smartphone, with two touchscreens.

Some implementations, that do not use the sagital axis, are presenting in phones like Nokia 3250 and Oppo N1, with twistable componentes: a keyboard, and main camera (doubling as a selfie one), respectively.

See more at "Form factor of mobile phones".