Heads 20% higher than American Standard B 18.2.1. Higher heads mean longer wear life and maximum holding for the nut.
SAE grade marks
The radial marks indicate the grade of SAE strength for better identification. Six marks on the head guarantee the quality grade 12.9 / 35-38 Rockwell (113/124 Kg./mm2)
Provides a correct flow of the steel fibre reducing the fatigue points ensuring major resistance to bumps and an even distribution of the weight. The edges do not round off and the bolts can be reused. The washer sits perfectly below the head.