Small clock is difficult to set. The modes and directions are not clear. When I can get the clock to show time, it is locked/stuck or only shows in 24-hour mode. The directions are inadequate and do not show all the options. So if a 12 hr mode is possible I sure could not figure it out. I got this as a gift for my working son, but after getting agitated with the settings and not finding 12 hour, I purchased him a different model and type.