Max-Prop 70 Millimeter Universal ZINC ( 70mm ) with aluminum retaining ring - Weight 0.96lbs Max-Prop 70 Millimeter ( 70mm ) For use with new and old generation Max-Props - Sea Shields Max-Prop Anodes use an aluminum retaining ring for longer life and improved bonding. Traditional Max-Prop anodes loosened and fell off, as the retaining screws being so close to the edge, became exposed as the anode naturally corroded. The majority of the anode was unusable, and had to be replaced prematurely. Units sold individually as one anode only.