TTV Ductile Iron Lugged Aluminium Bronze Disc TTV Butterfly ValvesNow Fully WRAS Approved Valve & EPDM Seat TTV Ductile Iron Lugged Butterfly Valves with Aluminium Bronze Disc & EPDM Seat The TTV Ductile Iron Lugged Butterfly Valves with Aluminium Bronze Disc are now fully WRAS approved, meaning both the EPDM seat and the entire valve assembly are certified for use with potable water. Built for strength and durability, these valves feature a rugged ductile iron body and a corrosion resistant aluminium bronze disc,