• 9. What is Oviko V type ball valve feature ?
• 8.What is oviko top entry ball valve feature ?
• 7. What is your blow-out proof stem design?
• 6. How about the underground ball valve feature ?
• 4.What is Emergency sealing ?
• 5.What is double block&bleed(DBB) design ?
• 3.What is automatic body cavity relief ?
• 2.What is anti-static device ?
• 1.What is anti-fire safe design ?