Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number R28 A75 found under Stone Cylinder Hone by Sunnen Products Company. The National Stock Number assigned to this part is 5345012142933, and the Federal Supply Class is 5345 Disks And Stones Abrasive. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like R28 A75.