6" RIV Cast Iron Knife Gate Valve Unidirectional Handwheel Operated AGRI Standard and PN10. RIV121This 6" RIV Cast Iron Knife Gate Valve is designed for unidirectional flow, making it ideal for agricultural applications. Its handwheel operation and AGRI Standard and PN10 certification ensure efficient and reliable performance. Made of durable cast iron, it offers long lasting use. To suit PN10 and AGRI Standard Square Flanges 4 Hole Cast Iron Body Stainless Steel Blade NBR Gaskets Fully Enclosed for Safety, with Position Indicator Handwheel