Kodak revised its whole line of Instamatic models using 126 film to coordinate with the 1970 launch of Magicubes, which fire mechanically rather than needing batteries. The X-90 is an update to the earlier range-topping Instamatic 814 to work with the new flash standard (although this model still requires a 3-volt alkaline battery to power its autoexposure circuit).
Premium features include rangefinder focus, user-selected shutter speeds, and a quirky pull-tape which winds up the automatic film-advance spring drive. The lens is a 38mm f/2.8 Ektar, indicating superior quality.
~Description courtesy of Camera-Wiki