this be a great little clock . I have have three , give away one `` new in the Box , '' or `` NIB , '' be order another to have on hand when the spirit move I to pass it on to someone . I be kind of a time freak , so I have get one in my bathroom , another in the family room , and a much larger `` atomic '' wall clock right over my pc . ok , its not atomic . it be digital , and it receive radio signal from a US station that tell it what time it be . you never need to set it . could not set it if you try . once you have feed it a aa battery , set it up accord to the instruction , and wait several hour some evening , it will display the exact time , to the minute . if you be willing to wait up to 59 seconds , you can get the exact time to the second , when the minute display role over to the next minute . yes , you can fold it up , pack it into you baggage , and set it up at you destination . BUT , if you travel take several day , and if you destination lodging have thick wall and few window , it may not pick up a signal . take it camping ... no problem unless it rain on it , or a bear eat it . and , it pretty much have to be in the USA , although I bet part of Canada , and maybe even northern Mexico , can pick up the signal , too . bad part ? the part that make I give it only four star ? set it up be a pita . yes , the instruction be indeed print right on the clock ... on the inside of the lid , which fold back to be the underside of the base . hard to read when you be set the clock use the button on the back of the clock , and watch the display on the front of the clock . also , everything require multiple button push of specific button ... one push too few , and you do not get what you want . one push too many , and you have to start over . try to set the clock while read the instruction off of the base be a loser . oh yes , you can set it up for 12 hour time , or for Navy time : right now it be `` 22:43 '' on `` MO 9.21 '' that be 10:43 pm on Monday , September 21st , for you land lubber . the url for the clock 's instruction be cleverly print right on the back of the clock . no , not the base , the back of the clock , right on the battery door . my suggestion be to go to this url :  and decide if you be sufficiently endowed with the necessary button push skill . if so , PRINT OUT the instruction and then order the clock ! its a doozy ! as for battery , I would use a common nicad aa to set it up the first tim . when that die , or be die , put in a lithium cell . that way you will only have to set it once every couple of year .