A beautiful glass decoration. 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 edges, and the surface will not run out. A fly can fly directly from the inside of the bottle to the outside without crossing the surface. It was developed by the famous mathematician Felix Klein in 1882. Specification: Material: glass (No wood base) Size Chart: 12x23cm/4.72x9.06 inch 17x9.5cm/6.69x3.74 inch 11.8x6.3cm/4.65x2.48 inch Package Includes: 1X Klein Bottle Note: 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 online shopping Specifications: Material: glass (No wood base) Size: 12x23cm/4.72x9.06 inch 17x9.5cm/6.69x3.74 inch 11.8x6.3cm/4.65x2.48 inch Note: 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 online shopping Package Includes: 1X Klein Bottle