Features:

1. Its easy to install and remove. 

2. 100% sink, it's excellent for your aquarium.

3. Can grow aquatic plant or moss.

4. Can be used for purifying water quality, It's harmless to shrimp and fish.

5. Small ceramic balls inside

Product Parameters:

1. Material: plastic

2. Product weight: about 30 g

3. Diameter: about 5 cm

4. Height: about 2.5 cm