Hello! Sorry for addressing this problem a little late.
Here's to clear up some misconceptions:
--->
If you can choose a color, you can surely choose a size. The item is not sold out unless there is no color option at all.
---> If you couldn't choose a size after choosing a color, then there might be a problem with your browser's configuration. If you are not already using Internet Explorer, kindly try switching your browser to Internet Explorer to see if the size option works.
If the problem still persists,
contact AsiaJam.com with your browser type, version and operating system (eg. Internet Explorer 5.0 Windows XP)
Thanks and good luck!