My hang board is built on a grid of t-nuts for maximum adjustability. I use these pinch blocks in combination with the Grip Training Blocks, a few Yaniro pockets and a set of system slopers. I attach these with just the bolts so that I can adjust the angle. They don't spin, even without set screws, and even with a fair bit of weight hanging from my harness. The texture is grippy without being so aggressive that it shreds the skin. Great product.