I did a search in the expressions forum and found this countdown timer. Just create a comp 15 minute long. Press "cntl+alt+shift+T" to create a text layer. Copy the entire expression written below. Twirl open the text and "alt + click" the source text stop watch to enable expressions, then paste expression below into the box. Lastly, make sure the text is right justified.

`rate = -1;`

clockStart = 900;

function padZero(n){

if (n < 10) return "0" + n else return "" + n

}

clockTime = Math.max(clockStart + rate*(time - inPoint),0);

t = Math.floor(clockTime);

min = Math.floor((t%3600)/60);

sec = Math.floor(t%60);

min + ":" + padZero(sec)

Johnny Cuevas, Editor

ThinkCK
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."

---THOMAS EDISON on inventing the light bulb.