DIN 137 spring washers.
DIN 137 TECKENTRUP lock washers.
DIN137 lock rings SCHNORR lock washers S.
Metric DIN137 Spring Lock Washers are specialty spring lock washers – Unlike standard split helical spring lock washers, the DIN 137 lock washers are uninterrupted formed disks in either a curved or waved configuration that are non-directional allowing the screw and or nut to be tightened in a clockwise or counter clockwise manner.
When compressed by tightening the nut, the DIN 137 lock washers exert a spring force between the tightened bolt and the substrate creating frictional resistance to rotation.