colsep

column separators (vertical ruling). Specifies the presence or absence of column separator rules. Provides the default value for all descendant elements. 
If colsep is non-zero, display internal column rules to the right of each entry; if zero, do not display the rules. This value is ignored for the rightmost column, where the frame setting applies. 
Default: IMPLIED (implies value from stylesheet if available, otherwise inherited value (inheritance path = table, tgroup, colspec, entry), if not, implies "1").