Large Steel Stacking Ball Corner. Product I.D.: 4HARCOR1991B2 Outside Dimensions: 3-1/8" x 3-1/8" (wdh) Attachment Hole Size: 3/16" (6 each) Product Weight: 3 oz. each Product Material: black powder coated steel. These Heavy-duty steel ball corners are great for larger cases. Two sides have a indent for use with multiple cases for stacking. Ideal for corner protection on crates, generic cases, tool boxes, etc.