Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4N3181 found under Starter Engine Electrical by Caterpillar Inc. The National Stock Number assigned to this part is 2920012911021, and the Federal Supply Class is 2920 Engine Electrical System Components Nonaircraft. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 4N3181.