Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number GRD-0502-HR found under Transducer Ultrasonic Test by Technisonic Research Inc. The National Stock Number assigned to this part is 6635013537789, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like GRD-0502-HR.