The NORD-LOCK® wedge locking washer pair according to DIN 25 201 is a purely mechanically functioning machine element that secures the screw connection through pre-tensioning force instead of friction, making it superior to conventional screw locking methods. When the screw or nut is tightened, the radial ribs of the NORD-LOCK® locking washers form a positive fit into the counter surface. The washer pair sits firmly in place, and movement is only possible between the wedge surfaces. Even with the slightest rotation in the loosening direction, the wedge effect increases the pre-tensioning force - thus, the screw secures itself. NORD-LOCK® provides reliable screw locking, even under extreme vibrations or dynamic loads. Due to the high hardness of the washers, they can also be used with high-strength screws up to and including strength class 12.9. d(mm): 25.3 D(mm): 39 Surface: zinc flake coated T=Thickness of the pair (mm): 3.4 for ø: M24 Size (mm): NL24 Content (PAA): 100.