purchase the clock a few month ago , and after play with it for 30 min . figure out how to set the clock from 12 hr to 24 hr , alarm clock time , turn the alarm on\/off , and change the temperature from centigrade to farenheight and vice versa . also , the sd option under the setting that lool like : -- sd be where you adjust the display to stay on all the time vs. clap it on . ignore review that say it be not possible to constantly keep the screen display on . if they have take the time to figure it out instead of give bad review , they would have save themselves some grief . the cube clock measure approx . 3in x 3in x 3in . it be small , however after watch the price for a few day , I purchase it for $ 5 with a shipping cost of $ 3 or so . so , if you want it for a cheaper price be patient . if you want it then and now for cheap , that be you problem . the only downside I see with this product be more likely a manufacturer defect and user error . I buy some cheap alkaline battery for it -- since it be cheaper to buy it without the dc 6v charger -- and after a few day of use , the display be random and no longer display the time . take the battery out and reinsert they , a few hour later it do the same thing . I replace the battery with some non-alkalie , higher quality duracell after a few day without use . this seem to work for a day , however it have the same display issue the next day and be leak battery acid . the instruction it come with be Chinglish at best so I throw they out a while ago . however , the device be likely not compatable with alkaline battery , so I 'll take that as fault on my behalf . give this clock 4 star , for good design , it do function , price , and ease of use . it lose one star to the lack of readability of the instruction and the fact that I have to throw it out . however , I be already plan on buy the larger wooden led clock as a replacement . needless to say I would buy it again .