Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number LL57U40J6 found under Screw Cap Socket Head by Long Lok Fasteners Corporation. The National Stock Number assigned to this part is 5305000602540, 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 LL57U40J6.