Simpson Swan Secure T13A250SNJ 2-1/2-Inch by 0.090-Inch Type 316 Stainless Steel Ring Shank with 15-Degree Wire Coil and 13/64-Inch Head, 1800-Pack 15 Degree Wire Coil Checker Pattern on Heads blends with Wood Grain, Reduces Glare Annular Ring Shank increases pull-out resistance Type 316 Stainless Steel Slender Gauge and Diamond Point for Easier Driving