Legrand - On-Q F2242 2.5Inch Grommet Ring GROMMET RING: Grommet rings are ideal for structured wiring distribution. OIL-RESISTANT: It protects enclosure and attaches to top of enclosure. And also, it is Oil-resistant rubber construction. ATTACHMENT: Grommet rings are attached to the top of enclosure. AVAILABLE SIZE AND COLOR: Grommet ring is of opening size 0.4 x 2.8 x 2.8 inches for a single quantity package and 3.9 x 2.8 x 1 inches for double quantity package. BEST SELLER GROMMET RING: Grommet rings is the Amazons Best Choice.