Abstract: A device for viewing stereoscopic 3D images using an electronic device with a screen display includes: a head fastener; a holder to receive and removably accommodate the electronic device in an accommodation space; a lens focusing light from the screen display to the eyes of the user; and a distance part, providing a predetermined distance between the lens and the screen display. The lens part provides a first image from a first part of the screen display to a first eye of the user, and a second image from a second part of the screen display to a second eye of the user. The holder part is supported relative to the lens by the distance part, the distance part being arranged to be reversibly collapsible, from a fully expanded state, in which the lens part is arranged at said predetermined distance from the screen display, to a contracted state.