M4-0.7X12 Metric Din7985A Phil Pan Sem type H Din127B Split Lock washer Full Thread 18-8 Stainless (Pack Qty 4,000) BC-M412SPP188

The washer/screw assembly makes this a locking screw with the washer providing the locking action. Machine pre-assembly provides cost savings to the end user. The spring lockwasher variety is preferred for use with hardened bearing surfaces Screw: Class 4.8 steel. Rockwell B 71 - 99.5 Spring Lockwasher: Spring Steel. HV 350 - 425