Catalina changed from a round mounting shaft to a double "D" shaft in about 2000. Unfortunately the actual date of the change was not recorded. Double "D" refers to the two flat sides threaded plastic mounting shaft. The engine panel or engine pod will have a matching hole shape.

• Length of stem: 1.20
• Diameter of stem at threads: 0.77"
• Diameter of stem at flats: 0.73"
• Diameter of body: 1.55"
• Overall length (incl terminals): 2.78"