Single shields are used where the cable or wire may pass through the hole. Ream pilot hole in single piece shields oversize for the size grommet used. Two piece shields are used over cables or wires with large end-fittings or existing installations. Actual hole size in 2 piece shields is slightly larger than indicated to prevent chafing cable. Dimple shields accommodate rubber grommets up to 7/8″ outside diameter. Shields may be installed with screws, bolts, plate nuts or rivnuts. Install cable and grommet in firewall, center shield on cable, drill attach holes, Shields have 5/32″ mounting holes. Note: if more than one cable passes through grommet fire resistant sealant must be applied to grommet. Seals are designed to protect sealing material from excessive heat – not carbon monoxide in cockpit. Use extreme caution when installing.