Used in salt or brackish water, these aluminum rudder and trim tab anodes are manufactured to Mil-SPEC standards by Sea Shield Marine and available in sizes extra small, small, medium, large and extra large. These aluminum rudder anodes are lighter than their zinc counterpart and each unit is designed with an encapsulated nut which prevents fallout.  Here are the sizes of the machine screw depending on the mount size.

  1. Extra small mounts with 10-24X1″ machine screw.
  2. Small mounts with 1/4″-20X1-3/4″ machine screw.
  3. Medium mounts with 1/4″-20X2” machine screw.
  4. Large mounts with 5/16″-18X2″ machine screw.