Furniture Rehab Set of two grommets to hold the drive tube in place on your Reclining Mechanism. Each grommet fits on either end of drive tube to create a snug fitting inside lift Mechanism. The outside lip measures 1 inch. Inside the opening is 5/8 inches. And the external protrusion is 3/4 inches. This grommet goes with a 5/8 inch drive tube.