18-8 Stainless Steel Spring Lock Washer Curved DIN 137A for M4 Screw Size 4.3 mm ID 8 mm OD, 100PK

The arched shape of these washers presses up against a bolt and down against a nut to prevent loosening from wear vibration or temperature changes. Similar to a spring they flatten out as pressure is applied helping to absorb shocks. They grip bolts more tightly than split and tooth lock washers. Unlike split lock washers which can only be tightened in one direction these washers have a continuous body that can rotate in either direction.Conical and curved washers are functionally the same and are often referenced using their DIN specifications. These DIN specifications refer to slight differences in OD and thickness. DIN 137A is the standard for curved spring lock washers; although this is no longer an active standard its still commonly referenced.Stainless steel washers are more corrosion resistant than steel and almost as strong. 18-8 stainless steel washers will hold up in wet and humid environments but will corrode if exposed to salt water or chemicals.