Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number USAPATENT1-579-449 found under Filter Mask Protective by Martindale Electric Company Inc. The National Stock Number assigned to this part is 4240006405188, and the Federal Supply Class is 4240 Safety And Rescue Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like USAPATENT1-579-449.