This is a 5/8 inch or 16 millimeter pin that works for squat racks or strength racks. It’s suitable for 3x3 or 75x75 racks. But I guess it would also work for smaller racks with the same pin holes.It’s not meant to hold any significant weight.For example, it is used to secure J-hooks. I drilled small holes in it to hold tiny magnets, allowing them to stick to the rack without slipping out. I printed mine using PLA.