Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 53D3972 found under Container Mask Fire Fighter by Crdaniels Inc. The National Stock Number assigned to this part is 4240005712240, 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 53D3972.