Contact Washers are conical shaped lock washers formed with a ribbed top surface. The conical shape exerts locking force 360° around the underside of the screw head or nut. The ribbed top surface further enhances the locking force and resists the torque fastener connection potential for loosening under pressure and vibration. Contact Washers are made from high carbon spring steel or stainless steel. They are manufactured in a variety of ID, OD and Thickness combinations to suit various applications. The washers are produced in accordance with French National Standard NFE 25-511 and Siemens SN 70093. Contact Washers can be ordered with either a plain smooth bearing surface or with barbs for grounding purposes when mounting surfaces are painted or coated.