This unique, write on wipe off time tool allows students to measure time in a number line format where they can visually see where the time goes. Think of this time tool as an analog clock unwound into a 24-hour format with a.m. marked in red and p.m. marked in blue. Hours are divided into five minute increments marked with dashes and 15 increments are also noted. Great for elapsed time and duration of time questions. This demonstration ruler measures 60" x 5 1/2" and expands to 12' in length.