Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 6181-138 found under Valve Bypass by Air Dry Co Of America Llc. The National Stock Number assigned to this part is 4810011863119, and the Federal Supply Class is 4810 Valves Powered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 6181-138.