High Purity Fused Quartz Frits/Porous Sintered Filter/Fritted Glass Discs/Quartz Glass Sintered High Purity Fused Quartz Frits/Porous Sintered Filter/Fritted Glass Discs/Quartz Glass Sintered of our company are made of high purity fused quartz sand with content SiO 2 > 99.99% and high temperature resistance up to