MERCURY QUICK CHANGE ANODE ONLY ZINC USED IN MERCRUISER SIZE: 3/8" THK. X 2 7/32" DIA. WEIGHT: .225 LBS M-706188 Aluminum Adapter is used in conjuction with M-706189 and M-706190. Used with Mercruiser Alpha and Bravo Sterndrives / Outdrive. It takes 2 screws to hold the adapter plate and 1 screw to hold the anode on the adapter plate . Aluminum adapter plate with stainless steel 10/32 threaded insert for long life