ID means inside diameter. A 1-inch ID rubber grommet has a nominal bore of 25.4 mm. This measurement does not specify its groove diameter, mounting-hole diameter or flange outside diameter.
Check the remaining dimensions
Confirm the mounting-hole size and panel-thickness range on the drawing. Review the groove width, flange overlap and overall thickness. Two grommets with the same 1-inch bore can fit different panels.
Confirm cable and material requirements
Check the cable or bundle dimensions and the required clearance, including connectors. If sealing is required, use the cable range and installation conditions specified for a suitable sealing profile rather than assuming that an open bore forms a seal.
Select the compound for the actual temperature, fluid and outdoor exposure. Custom manufacturing can be reviewed from a customer drawing or existing sample.
