18" tall hard clear plastic body and legs with vinyl head, arms and shoes, sleep eyes with metal internal mechanisms. 1964. This doll and the previous item #1453 are both from a former Mattel engineer who worked at the main plant in California during the 1960s. As an engineer, he was responsible for making sure the plants ran smoothly and if toy production had a problem, he would try to help the plant production get back up as quickly as possible. To assist the engineer, a few prototype examples of each new toy would be made in clear plastic so the working internal mechanisms could be easily seen. This allowed the engineer to more easily troubleshoot any production problems and come up with solutions to get production resuming. Because the Hong Kong plant worked at different hours than the California plant, Mattel engineers were one of the few employees actually given permission to take prototypes home in case an early morning trouble call came in. This particular prototype doll is actually quite rare for it was the first model of a doll that was ever able to walk mass produced. Hundreds of engineering hours were spent trying to figure out how to make a doll walk and not fall over. This is the first prototype of that model. It went on to be a top seller for Mattel. All internal mechanisms are clearly visible. Clear plastic body and all vinyl parts are Exc./N. Mint. Doll still retains plastic band around hair as produced.