Cylindrical head screws - Import export

The effective protection against self loosening and unscrewing. The "SK" Serrated Locking Washer prevents self-loosening of screwed joints. Damage to the bearing surfaces and consequent variations in the tightening torques, as they occur in threadlockers with teeth are avoided with lock washers through the special geometrical shape of the locking edges. shape S (small) shape M (middle) shape B (wide) shape Z (for screws with cylindrical head shape) shape K (for electrical contacts)