Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number RD240B1B4 found under Knob by Korry Electronics Co. The National Stock Number assigned to this part is 5355012940431, and the Federal Supply Class is 5355 Knobs And Pointers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like RD240B1B4.