Plastic Slinkys ….. can be made in different colors. Many of them are made with the colors of the rainbow in rainbow order. Plastic Slinkys are more flexible and less deformable allowing them to be more easily reversed end-to-end without tangling. They were marketed in the 1970s as a safer alternative to metal Slinkys as they did not present a hazard when inserted into electrical sockets. The plastic spring toy, known as the Plastic Slinky was invented by Donald James Reum, Sr. of Master Mark Plastics in Albany, Minnesota. Mr. Reum came up with the idea as he was playing with different techniques to produce a spiral hose for watering plants. However, as it came off the assembly line, according to his children, it looked more like a "Slinky". He worked at it until it came out perfectly and then went to Betty James with his prototype. Mr. Reum manufactured the Plastic Slinky for Betty James for several years. Eventually Betty James decided to manufacture the product exclusively through James manufacturing effectively ending the production of the toy by the small Minnesota company. Reum's patent number, 4120929 was filed on Dec 28, 1976 and issued by the US Patent Office on Oct 17, 1978. See - http://en.wikipedia.org/wiki/Slinky From Yahoo we get a comment on the material used. ‘Since late 1978, the Slinky also is made of the plastic, K-Resin® styrene-butadiene copolymer from Chevron Phillips Chemical Co.’ See - https://answers.yahoo.com/question/index?qid=20061207094846AA9SzO3