Yes. When looking in both ends of the screw hole with the naked eye, there is different 30° wedge thread . But if the hole is small, it is more difficult to identify the unique thread.It can be  detected by such as gauge, borescope, etc.

Yes. The national standard nut has no directionality.ESLO 30° wedge ramp is only on one side of the female thread. Therefore, the lock nut has self-locking force only in one direction. Therefore, we recommend flange surface nut which instruct direction clearly.

No. The variable thread is specially designed for internal threads. The external thread is very difficult in machining accuracy.

This type anti-loosening thread technology has been tested in thousands of different applications. It has been widely used in aerospace, aviation, railways,automobiles, medical care, furniture, construction machinery and other industrial machinery, etc.

Firstly, the contact points are concentrated on the crest of the external thread, rather than near the pitch diameter side of the thread.This will greatly improve the mating performance of the threaded contact. Secondly, the crest of the male thread is engaged on a 30° wedge ramp,instead of contacti......

It's close to nylon insert locknuts, With the increase in the number of lock nuts produced, The cost of ESLO lock nuts are also declining.