Features: brand new and high quality For instructions, please look at the picture. Please pay attention to the bottle, please use the beverage bottle. The simplest is the bottle of drink, the size is completely suitable. Demonstrate a vortex in your classroom Show that in order for water to flow down, air must flow up. These amazing connectors screw onto two plastic soda bottles and allow students and teachers to create a water vortex. Or, connect two small soda bottles and make a sand timer. Color: Random delivery (If you buy more than one,the color you received may be the same color or different colors) Material: Safe Eco- friendly ABS Sales Way:Retail and Wholesale Size: One Size Length: 5cm (1.97in) Width: 3.2cm (1.26in) Height: 3.2cm (1.26in) Quantity: 1PC Note: If you have big quantity , please feel free to contact me, I will give you best discount, thanks Size For Manual Measurement, there may be a 0 to 2 for cm error, belongs to the normal phenomenon. And due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package includes: (Without retail package) 1 x Bottle Connector