NYLOC – nut with elastic nylon insert that prevents it from unthreading by accident.
自锁螺母- 螺母丝口内嵌入了一种弹性尼龙物，防止意外松脱。
2
It declines with the increase of times of direct assembling bolt knocked-down. But it can still reach that of nylon inbuilt nut after knocked-down 8 to 9 times.