CRL’s Trim Ring Drill-Thru Shelf Support for 1/2" (12 mm) glass shelves is a two-part Stainless Steel Clamp that is attached to the Cable with two socket head screws. The Trim Ring sits above the glass and covers the hole for a finished look. The Drill-Thru Support requires a 1/2" (12 mm) diameter hole for the cable. The weight capacity for each Drill-Thru Shelf Support is 175 lbs. (79.4 kg).