Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 427138 ITEM 17 found under Valve Check by Western Filter A Division Of. The National Stock Number assigned to this part is 4820013126708, 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 427138 ITEM 17.