[Inner diameter (d) 8.2×Outer diameter (D) 17.0×Thickness (t) 2.5]

When the hole diameter of the other material is larger than a screw, the screw head can be stabilized. The screw head seat is wider to increase the adhesion to the partner. For use in areas where you want to insulate. Prevents damage to the parts of the screw head seat when tightening. RoHS 2 compliant product.