You can see details of what is inside in the instructions for which I have included several photos. The mobile consists of five character images/pieces: Eric the Prince/film title; Flounder; Ursula; Sebastian; Ariel - plus the strings and hanger/hook.
The largest piece (the one on top) measures approx 15 W x 9H and the mobile pieces are made of what seems to be heavy cardboard. The item "Disney THE LITTLE MERMAID Rare 1989 Movie Promo Mobile" is in sale since Friday, March 22, 2019. This item is in the category "Entertainment Memorabilia\Movie Memorabilia\Merchandise & Promotional\Other Movie Promo Merchandise".The seller is "cheesypoofs2000" and is located in New York, New York. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Dominican republic, Panama, Trinidad and tobago, Guatemala, El salvador, Honduras, Jamaica, Viet nam, Uruguay.