NAS spacers are a type of fastener that is used to provide a physical separation between two objects. They are typically made of metal or plastic, and they come in a variety of sizes and shapes. NAS spacers are used in a wide variety of applications, including aerospace, electronics, and construction. The five NAS spacer types are: NAS42: These are sleeve-rivet spacers that are made of aluminum or steel. They are typically used in applications where a high degree of strength and vibration resistance is required. NAS43: These are sleeve-screw and bolt spacers that are made of aluminum or steel. They are typically used in applications where a high degree of strength and vibration resistance is required, but where a screw or bolt connection is also required. NAS61: These are nylon spacers that are used in applications where a high degree of electrical insulation is required. They are also used in applications where a high degree of corrosion resistance is required. NAS1056: These are sleeve-rivet spacers that are made of aluminum or steel. They are typically used in applications where a high degree of strength and vibration resistance is required, but where a lower cost is desired than NAS42 spacers. NAS1057: These are sleeve-screw and bolt spacers that are made of aluminum or steel. They are typically used in applications where a high degree of strength and vibration resistance is required, but where a lower cost is desired than NAS43 spacers.