3M 4000 Marine Adhesive Sealant - 3 oz

The same sealant used on the factory floor when your boat was built. 3M 4000 creates a watertight, non-corrosive seal on thru-hull fittings above or below the waterline - exactly what you need when adding a ballast system.

Fast cure (24 hours), white finish, and built for metal fitting connections. One 3 oz tube seals 18-20 fittings, so a single tube handles a complete ballast install with product to spare.

If you're running new thru-hulls for a ballast upgrade, don't skip the sealant. This is the right product for the job.