Usage Tips:Features: Magic Magnetic Ferrofluid Liquid Display Bottle: The Ferrofluid magnet display bottle is magic bottle that the inner black Ferrofluid can react in novelty and fascinating way and turn into various magic shapes when magnet is close, free change by the magnet controlling. Easy to Control: The magnetic ferrofluid which is easily to operate by the magnets(NOT included), you can control the fluid by moving the magnets to close or away, up or down, make it turn into various magic shapes as you like, or to control them dancing in the bottle, perfect desktop decoration for your office, home tables and etc. Stress Relief Toy: The black ferrofluid bring you to mystery world, change their shape by control the magnets speed or force, combination of magnets to control it, help release adults and teens daily stress & anxiety. Science Toy: The Ferrofluid bottle well displayed the fluid movement by participate and playing, which is attractive and popular for kids, teenagers, let them know the ferrofluid perfectly and also suitable for window display or desk decoration. Great Gift: The ferrofluid display bottle is great gift for children & adults as birthday gift, Christmas gift, housewarming gift which is suitable for kids, family, colleagues, friend and hobby collectors. Specifications: Product Dimension: approx. 9.5x10cm/3.74x3.93inch Material: Glass, Ferrofluid Net Weight: approx. 370g/0.81pound Note: Warning: The toy may contain small accessories and need to pay attention to the swallowed risk. Please allow 1-2cm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1 x Ferrofluid Display Bottle