Casio ALT-6100. Released in 1993, this rugged model was designed for mountaineers or outdoor hikers, who would find useful its multiple recording functions of altitude, temperature and atmospheric pressure.
This made in Japan example is in used but good functional condition. The crystal and the back plate have scratches, but all the screen display is readable. No missing segments are visible. All the buttons work was intended, as well as the sound and the light.
Feel free to ask questions.