Split Grommet Seal 1/in Hole 4in O.D.

The SEALS-IT Split Grommet Seal with 1-inch hole and 4-inch outer diameter is engineered for professionals who demand reliable firewall penetration solutions in custom automotive builds and restoration projects. This split-design grommet seals engine bay openings where wiring harnesses, fuel lines, or brake tubing pass through the firewall, preventing dust, moisture, and exhaust gases from entering the cabin. Whether you're fabricating a custom hot rod harness, retrofitting modern electronics into a classic vehicle, or running auxiliary systems through existing firewall penetrations, this grommet provides a factory-quality seal without requiring full firewall drilling.

Constructed from a combination of aluminum and natural rubber, the SEALS-IT SGS45500 features a split design that allows easy installation around existing lines without disconnection or removal—a critical advantage in tight engine bay environments where access is limited. The 0.125-inch wall thickness provides structural integrity while the rubber component compresses to form a watertight seal around round or oval conduit. The flat profile and 5-inch mounting dimension accommodate standard firewall configurations, while the split construction means mechanics can simply separate the grommet halves, wrap around the existing line, and secure without partial disassembly of fuel or brake systems.

Automotive technicians, restoration specialists, and custom fabricators benefit most from this grommet when sealing aftermarket wiring looms, hydraulic lines, or pneumatic tubing through original or modified firewall openings. Its split-grommet design is particularly valuable in engine bay modifications where the firewall penetration already exists but lacks adequate sealing, common in engine swaps, turbo installations, or custom harness routing. The black exterior finish resists UV degradation in under-hood environments, ensuring long-term seal integrity through thermal cycling and moisture exposure.