These billet gas fills are machined out of 6061-T6 aluminum. With a low profile style, the outer edge features an oversized contoured knurl making for easy removal. They mount with three hidden screws (sold separately) and are 3 1/2″ in diameter. They accept 1-1/2” ID fuel fill hose and are vented (no need for an external vent. Available with a machined finish, bright polished finish or in a variety of anodized and Fusioncoated colors.