Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number A28-2 found under Knob by Dynatech Co. The National Stock Number assigned to this part is 5355001979328, 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 A28-2.