Martyr CME series marine anodes consist of a brass plug with an anode threaded into it. These anodes meet or exceed the specification of anodes supplied as original equipment.
Note: In spite of Fisheries' promotion of aluminum sacrificial anodes as a generally superior choice of material, pencil anodes is an application where zinc is the anode material of choice. This is because aluminum pencil anodes are known to break at the neck and end up blocking coolant channels. As a result, most engine manufacturers - Cummins, Yanmar, Caterpillar, etc. - still use zinc for pencil anodes, and you should too. In fact, Fisheries does not stock aluminum pencil andes for the above reason.