Corrosion-resistant, industrial-grade rat blocker for installation within a drainage chamber. Manufactured from marine grade 316 stainless steel. Twin flaps and sharp serrated edges help to prevent rats from passing the valve and entering the property. Configured for drain inlet or outlet positions. Suitable for domestic use in plastic, clay, concrete, cast iron and other pipe materials. Untreated Steel Construction For use Against Rodents Suitable Pipe Diameter: 100mm Suitable for Plastic, Clay, Concrete & Cast Iron Pipes Suitable for Domestic Use Twin Serrated Flaps Corrosion-Resistant Untreated Steel Construction For use Against Rodents Suitable Pipe Diameter: 100mm Suitable for Plastic, Clay, Concrete & Cast Iron Pipes Suitable for Domestic Use Twin Serrated Flaps Corrosion-Resistant