OCAL™ PVC-coated zinc grounded knockout hub. Captive sealing ring won't buckle or slip during installation and provides a complete 360° seal, even when conduit is not perpendicular to the enclosure. Hexagonal or splined body and locknut enables fast and easy installation. Insulated throat moulded from 105°C rated thermoplastic, UL94V0 flammability rated. Sharper and deeper teeth provide a more penetrating bite for improved bonding to the enclosure. Zinc or copper-free aluminium with a nominal 0.04 inch PVC coating bonded to exterior. Pressure-sealing sleeves protect connections.