Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 457173 found under by Mks Instruments Inc. The National Stock Number assigned to this part is 5865001353770, and the Federal Supply Class is 5865 Electronic Countermeasures Counter-Countermeasures And Quick Reaction Capability Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 457173.