Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 70R657 found under Coupling Tube by United Technologies Corporation. The National Stock Number assigned to this part is 4730016488451, 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 70R657.