Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number NAS1581A7H42 found under Screw Close Toleran by National Aerospace Standards. The National Stock Number assigned to this part is 5305011930153, and the Federal Supply Class is 5305 Screws. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like NAS1581A7H42.