... color, you can choose one or many kinds of colors.2) Protecting environment: Non poison, Non smell, Non pollution, Non cauterization ... , Safe.3) heat insulation: It can absorbs the energy from sun and ... ponds, aquariums and aggregate projects. Size range: 1-3mm,2-4mm,3-5mm,6-9mm,9-12mm ,12-20mm.20-50mm(size ...