For available sizes, quality and sales units click on the additional information tab. Please note, not all combinations are available. More information about BS-67 (67% SiO2) is available on the product page. More information about BS-64 (64% SiO2) is available on the product page. BS-64 diameters below 70mm are only available for orders starting from 100 kg. If you need quantities above 5 kg please request a quote.