Product information: This is a fish tank luminous stone. It will glow when placed in the fish tank at night, and it will have a very good effect. Material: Resin Specifications: The size is about 2-3 cm Instructions: After absorbing all kinds of visible light for 10-20 minutes during the day, it can continue to emit light for more than 12 hours in the dark at night. Its luminous brightness and duration are 30-50 times that of traditional ZnS luminous materials. It can be recycled indefinitely without radioactivity. Non-toxic and harmless to human body. Recommended use: Luminous stones can be placed in the water for a long time, and can be used for viewing in fish tanks, gardens, home decoration, etc., or they can be arbitrarily placed in shapes to bring surprises to friends in the dark.