These are highly polished solid metal flip over tops. They have a chrome like finish and are excellently machined. Simply spin it as normal and watch it suddenly flip over and then continue to spin upside-down. These flip over tops (often known as a The Tippe Top) were originally invented in 1950 by the Danish engineer Werner Ostberg. His inspiration can from a visit to South America where he had seen local people playing with a small, round fruit. When they turned it by the stalk like an old-fashioned spinning top, it would spin for a second and then invert and spin on the stalk. However some credit should be given to Helene Sperl who in 1891 patented a Wendekreisel in Germany. However the patent ran out and it was never mass produced. These tops are made from polished aluminium and are 29mm in diameter. SKU:ADIB004U3SPF0PROP 65 WARNING: This product can expose you to some kind of chemicals, which is known to the State of California to cause cancer For more information, go to www.P65Warnings.ca.gov