Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 2581 found under Bismuth Alloy Ingot by Belmont Metals Inc. The National Stock Number assigned to this part is 9650006274302, and the Federal Supply Class is 9650 Nonferrous Base Metal Refinery And Intermediate Forms. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 2581.