Its a digital clock with many functions like 12 /24 hr format , temperature, alarm and more. It runs on 3 batteries. Its has a white negative display , u can refer to the pics and works when u press the upper button. It needs to be cleaned frim the cell slots as they had caught rust so it sometimes work and sometimes stop but after service may work well.The battery slot is little bit tight , so adjust your batteries by rotating them where they work good ,when u need to replace them .Feel free to ask more in comments.

Battery slot need replacement rest all good.