Marble glue is based on unsaturated polyester resin, which is suitable for bonding between various stones or repairing cracks and broken marks on the surface of stones. It is often used in various stone paving projects and repairing, bonding, positioning and caulking of stones. The classification of invoice code refers to the tax code that should be approved by State Taxation Administration of The People's Republic of China when the goods on the taxpayer's face are invoiced. When issuing invoices, the tax authorities can conduct data statistics, screening, analysis and comparison according to the tax rate and collection rate indicated on the classification code, with the ultimate goal of strengthening collection management.