These are builder tabs for people on a budget. These are puzzled into our sheets when making other products- so we can offer them at a lower cost. All Economy Builder Tabs are laser numbered to avoid confusion. Sold Individually.
Features:

• 3 5/16 Inch Overall Outer Dimensions measured both ways. (84.14 mm)
• 1/2 Inch Holes (.510 Inch actual, 12.95 mm)
• 3/16 Inch Thick (.175 Inch, 4.45 mm)
• Works with 1.5 Inch O.D. Tube (38.10 mm) for Rollcages, flanges, frame gussets when lengthening, etc. We would not recommend using over 1.5 Tubing with this as you would have a hard time getting bolts to go in unless you were to weld this to something and use the holes as rosette welds.
• Measurement from 1/2 Inch holes vertical and horizontally is 2.125 Inch (2 1/8 inches)(53.98 mm)
• Measurement at a 45 degree angle is 3 Inch