If you buy 1 'single' you will receive 1 archway piece, if you buy 'double' you will receive 1 double archway piece with prefixed central column. If you buy 'treble' you will receive 2 archway pieces (single and a double with 2 separate central columns), if you buy 'quadruple' you will receive 2 double archway pieces (with 1 separate central column).
