HTV hollow core insulators mold 1.OEM 2.passed ISO 9001-2000 2.tooling&production 3.rich experience in this field we have so ... many experience in making HTV hollow core insulatos from 110kv ... material: P20, S50, S1363.Mold case material: S50,etc4.Mold core material: P20, etc5.Value-added service: polishing, nitrogen treatment, black ...