Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 7600-18 found under Seat Exhalation Valve by Siebe North Inc. The National Stock Number assigned to this part is 4240012503595, and the Federal Supply Class is 4240 Safety And Rescue Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 7600-18.