For wide range of Johnson and Evinrude outboards, 1981 through 2011, mounts under anti ventilation plate.
Length: 2-1/4″
Width: 1″
Thickness: 1/2″
Mounting Holes: 10-24 threads; 1″ center-to-center
EMP Aluminum anodes conform to Mil-Spec A-24779(SH)

also crosses with:
Canada Metals CM123009A
Performance Metals 00141A
GLM 12730
Technoseal 00912AL
Reliance AMD-327606