Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 400-037-18 found under Spring Helical Extension by Raymond Corporation The. The National Stock Number assigned to this part is 5360000182454, and the Federal Supply Class is 5360 Coil Flat Leaf And Wire Springs. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 400-037-18.