11/16 in_7/8 in Outside Dia, 1/4 in Inside Dia, Rubber Grommet Kit - 2MEV3|2MEV3 - Grainger
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Amazon.com : HORTIPOTS 1/4 Inch Rubber Grommet Pack of 25 Top Hat, 6 mm ID Small Tophat Grommet for OD 1/4 Inch Vinyl Rubber Tubing in Hydroponic and Irrigation Systems (Pack of
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Hillman 1/4 in. Inner Diameter - 9/16 in. Outer Diameter Rubber Grommet 55054 - The Home Depot