Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number A53999 found under Expansion Joint Pip by Senior Operations Llc. The National Stock Number assigned to this part is 4730013664060, and the Federal Supply Class is 4730 Hose Pipe Tube Lubrication And Railing Fittings. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like A53999.