3/8" Screw, 0.391" ID, Steel Internal Tooth Lock Washer MPN:SIWIS0370XUSA-1

This high-quality internal tooth lock washer boasts a 3/8 outside diameter and 0.391 inside diameter with stainless steel construction, providing unparalleled strength and durability for diverse applications. Its unique design incorporates teeth on its inner edge that bite into the surface of the fastener, offering secure retention while preventing spinning or loosening once tightened. The resulting strong clamping force is ideal for both internally and externally threaded bolts in high vibration, extreme temperature, or dynamic loading environments such as machinery, construction equipment, or automotive industries where reliable performance is imperative. In addition to its utility in new assemblies, it also serves as an effective repair solution when self-locking or adjustable lock washers are not feasible due to clearance issues or complex geometries.