Vauban-style fortresses had many elements. The main walls were often surrounded by outer defensive works to provide added protection. These usually consisted of a Glacis which were sloped earthworks, backed by masonry. There were also smaller triangular shaped bastions (sometimes called Ravelins) to provide extra flanking fire. PaperTerrain's outer works kits allow you to add these elements to your 4-sided and 50sided forts as well as Vauban City Walls. The 6mm scale kits include 15 angled Glacis pieces, 45 connector pieces, and 5 small Ravelins. The 10/12mm scale kit has 10 angled Glacis pieces, 36 connector pieces, and 6 small Ravelins. The 15mm scale and 20mm scale kits includes 10 angled Glacis pieces, 30 connector pieces, and 5 small Ravelins. The 25/28mm scale kit includes 10 angled Glacis pieces, 34 connector pieces, and 5 small Ravelins. All kits are available in either brick or stone finishes to match the fort kits.