Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number X21-5228 found under Fuseholder Block by Cleveland Motion Controls Inc. The National Stock Number assigned to this part is 5920011511208, and the Federal Supply Class is 5920 Fuses Arresters Absorbers And Protector. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like X21-5228.