MOONS LOCK NUTS, ALL STEEL, ANTI-LOOSENING & PAT. 

EL nut is a elastic torque-type steel nut that meets ISO 7040 mecanical structure, NAS 3350 for extreme vibration resistance, DIN 65151(Yunker) for axial vibration, and ISO 2320 for prevailing torque.  It has characteristics such as anti-loosening in extreme vibration, all-steel, self-locking, anti-displace, 
cryogenic -165℃, re-useable more than 5 times.

EL nut is a elastic tension torque-type steel nut that meets ISO 7040 mecanical structure, and ISO 2320 for prevailing torque.    It has characteristics such as anti-loosening in vibration, all-steel, self-locking, anti-displace, re-useable.  In particular, it has a high adaptability for small bolts with a screw diameter of 16mm, or less

PAR nut is a sheet metal nut with a spring, and meets NAS 3350 for extreme vibration resistance and DIN 65151 for axial vibration.   In particular, it shows good performance in railway tracks, floating solar power.   The low height of the nut makes it suitable for additional reinforcement work or maintenance preservation. 
It has a track record of application in various fields including railways. END