Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 555-5524 found under Block Bearing by Northern Telecom Inc Telecom Dis. The National Stock Number assigned to this part is 6340008622023, and the Federal Supply Class is 6340 Aircraft Alarm And Signal Systems. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 555-5524.