Tecnoseal Rudder Anode - Aluminum - 3-3/4" Diameter. The Tecnoseal R3AL Rudder Anode w/ Stainless Steel Hex Nut and Socket Cap Screw features a captive hex nut that is great for underwater applications. For a good way to ensure you are using some of the best gear the maritime trade has to offer purchase the Tecnoseal R3AL Rudder Anode w/ Stainless Steel Hex Nut and Socket Cap Screw. Specifications for Tecnoseal R3AL Rudder Anode: Manufacturer: Tecnoseal Color: Silver Package Contents: Tecnoseal R3AL Rudder Anode Tecnoseal R3AL: R3AL Rudder Anode - Aluminum - 3-3/4" Diameter