Firewall plug for various Honda and Acura vehicles when removing factory heat piping. This piece replaces the rubber grommet through the firewall PN: 79731-SH3-000. This is a high quality 2 piece HPDE Plastic plug CNC cut to exact dimensions and screwed into place from inside the vehicle. A bead of silicone sealant is optional to make the installation more weather resistant but not required.