The marina I keep my boat at is notorious for Electrolysis issues. I used to get my zincs from another store that didn't sell Camp products, and would have to change my tab zincs halfway through the season. My neighbor told me he bought his from Jamestown and didn't have a problem with them. I started buying the same ones and haven't had a problem since. I'd have to say something about Camp zincs make them last longer than the other brands.