A beautiful glass ornament.Can be used as a gift for your child's scientific enlightenment.The Klein bottle is a non-orientable topological space.It has no internal and external distinctions, no for edges, and the surface will not end.A fly can fly directly from the bottle to the outside without crossing the surface. It was developed by the famous mathematics in 1882. Felix Klein proposed.Specification:Material: glass(No Wooden Base)Size Chart:12x23cm or 4.72x9.06 inch17x9.5cm or 6.69x3.74 inch11.8x6.3cm or 4.65x2.48 inchPackage Includes:1X Klein BottleNote:1. Please allow slightly error due to manual measurement.2. Due to the difference between different monitors, the picture may not reflect the actual color of the item.3. Wish you a wonderful on-line shoppingSpecifications:Material: glass(No Wooden Base)Size:12x23cm or 4.72x9.06 inch17x9.5cm or 6.69x3.74 inch11.8x6.3cm or 4.65x2.48 inchNote:1. Please allow slightly error due to manual measurement.2. Due to the difference between different monitors, the picture may not reflect the actual color of the item.3. Wish you a wonderful on-line shoppingPackage included:1X Klein Bottle