Split lock washers feature a spiral design made to keep threaded fasteners from loosening.  This lock washer grasps the material and allows for a secure connection preventing loosening from vibration. 

High Collar Lock Washers

Split lock washers feature a spiral design made to keep threaded fasteners from loosening.  This lock washer grasps the material and allows for a secure connection preventing loosening from vibration.  High collar lock washers are designed to fit under the head of a socket cap screw.  The high collar lock washers are typically used where vibration may occur.