this have a large display and be therefore easy to see even with the unaided eye . I do not need the clock as a alarm so I can not rate that function . also , I do not know if the DST feature work since no DST date have pass yet . but if you want a easy to use and easy to see clock , this be it . I just order two more . a peek at the instruction tell how to set the time manually if you so wish , and also how to change the battery . instruction be wonderful thing . since there be two dimension for the clock on Amazon web page just let I clarify : dimension be 3 1\/4 `` h x 7 1\/8 `` w x 2 3\/4 `` D. so a pretty small footprint . this be not to be confuse with a `` atomic clock '' . there be no radio signal and the clock operate on house current with battery backup and reset itself after a power interruption . update 3 month later I do buy two more clock for a total of three . all keep accurate time and change day light savings time correctly .