4th leaf plus 4 extension brackets required for the extended 4-leaf dining setup.
 
The set includes one table leaf with overlapping/underlapping spill stop joints at either side plus 2 pairs of extension brackets. This 4th leaf is identical to the existing  middle leaf of your standard 3-leaf table top.
 
The brackets are used to extend each end of your standard tabletop set a further 225mm beyond the supporting frame, allowing the extension leaf to sit tight within the gap, to create a virtually seamless 4 leaf top.