Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 2191B0053-3 found under Tank Coolant Fluid by The Boeing Company. The National Stock Number assigned to this part is 1660015936808, and the Federal Supply Class is 1660 Aircraft Air Conditioning Heating And Pressurizing Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 2191B0053-3.