There are ceramic ball, coral stone, activated carbon for water filtration or aquarium landscape, you can choose one for your need.

Features:
Ceramic ball can filter water quality, often used for shower nozzle, tap filter or water dispenser filter core.
Coral stone, pure natural coral fossils, rich in micropores, often used for aquarium landscape and moss growth.
Activated carbon can be used for water purification (domestic and industrial water), odor adsorption.
Natural raw materials.
Make your life more healthy.

Specifications:
Material: Natural
Type: Ceramic Ball, Coral Stone, Activated Carbon (optional)
Item Size:
Ceramic Ball: 10mm / 0.39in
Coral Stone: 10-40mm / 0.39-1.57in
Activated Carbon: 10-40mm / 0.39-1.57in
Item Weight: 100g / 3.53ounces
Package Size: 120 * 80 * 30mm / 4.72 * 3.15 * 1.18in

Package List:
1 * Bag of Activated Carbon