Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 91S2 found under Transistor by Sperry Rand Corp. The National Stock Number assigned to this part is 5961009815786, and the Federal Supply Class is 5961 Semiconductor Devices And Associated Hardware. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 91S2.