This is a set of back pipe casts from James Cameron's 1986 sci-fi classic Aliens. These master pattern castings were used to create new production molds as a back measure if any should break and were a key part of the alien's design, adding to their gruesome mystique. These pieces were used to create the fin and back pipes which are located on the back of the aliens and can be seen during scenes when the star studded cast of Marines wages war against them. The set here includes four back pipe pieces and one back fin. The pipe pieces are made from plaster and have been fully detailed but painted solid gray and are each attached to a small round base. The fin, which has a flat bottom with a short metal peg sticking out, also features a curvy design with bone like pieces protruding from each side. Each pipe measures approximately 17" x 7" x 7" (43cm x 18cm x 18cm); the fin measures approximately 16" x 7" (41cm x 18cm). The pieces included here have become dirty and somewhat worn due to production use and age but remain in fair condition.