Width works for me also.
px; - adjust as required.
border-right:3px solid #E0E0E0;
Using pixels for size is not always a good idea. Using ems or %ages make it easier to write for different screen sizes. If you look at my site here, http://exitfegs.co.uk/Sources.html
You will find that the three columns are sized in %ages. This was suggested to me by AeroSpace_Eng who largely re-wrote this for me. It survives and stays readable if you pull the sides around. If it were sized in pixels, it would break up and become a mess.