Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number GM21057-KA2S found under Cap Protective Dust And Moisture by Western Branch Diesel Incorporated. The National Stock Number assigned to this part is 5340016205713, and the Federal Supply Class is 5340 Hardware Commercial. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like GM21057-KA2S.