Spirol® Coiled Pins are designed with a unique 2-1/4 coil, allowing them to compress evenly and distribute stress equally. They compress from the outer edge inward, so force direction does not reduce flexibility or shear strength - as loads are applied from any direction, these pins compress into a solid tube. And since flexibility, strength, and diameter must be in proper relation to each other and to the hole, EFC offers the Spirol® Superflex version in Standard and Heavy Duties to suit your specific needs.