Triplex duct plugs are split plugs for sealing around, organizing, and supporting up to three subducts, pipes, or cables. The plugs are designed for use in round openings such as conduits, conduit fittings, and core-drilled wall penetrations. Effective long-term watertight and airtight seals, these products also prevent mud, backfill, and slurry from entering handholes, manholes, and buildings during the construction process.