MS24665-227 is a Military Standard corrosion resistant steel cotter pin used to lock castellated nuts and bolts in aerospace and mechanical assemblies. It functions as a positive locking device inserted through a drilled fastener or shaft and bent over to prevent nut rotation and loosening. Intended applications include aircraft airframe and hardware locations where a 5​/​64 inch diameter by 1​/​2 inch long cotter pin is specified to secure critical joints.