8-1616359-4 is a lock washer designed for use with #4 fasteners. This washer features a thickness of 0.035 inches and is designed to prevent loosening of fastened components under vibration or torque. The product is EU RoHS compliant and EU ELV compliant, meeting environmental and safety standards. Lock washers like this are commonly used in electronic assemblies, mechanical fastening applications, and equipment where secure connections are essential.