Hole shape: square Constructed from scratch-resistant epoxy-coated steel that will never crack, break or wear out over time Mounting hardware is hidden from sight, presenting the clean, attractive and durable appearance Use with LocHook 50000 Series 100% heavy-duty steel 2 and 4-point contact locking hooks 2 boards can be mounted vertically or horizontally together or positioned on multiple wall areas Ideal for heavy, over-sized and odd-shaped professional power, hand and maintenance tools and more