A screw insulator can also be known as a shoulder washer. The screw insulator is designed to insulate screws, rivets or wire from an assembly.Features and Benefits of a screw insulator• Thermally insulate a screw from making metal to metal contact• Reduce Vibration• Act as Spacers and Guides• Are Strong and Corrosion Resistant• Can be Used as Seal in Some ApplicationsWhy and when to use a screw insulator?Screw insulators can be inserted into a housing to provide a bearing surface for rotary applications.The flange on the screw insulator is used to locate the bushing when it is installed or to provide a thrust bearing surface.Screw Insulators are used to prevent heat flow through the screw to other parts of the thermal assembly.