Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number LL-1408 ITEM 18 found under Seat Valve by Olmsted Products Company Llc. The National Stock Number assigned to this part is 4820012250047, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like LL-1408 ITEM 18.