Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number R-25999 found under Disk Valve by Emerson Power Transmission Corpo. The National Stock Number assigned to this part is 1660000833601, and the Federal Supply Class is 1660 Aircraft Air Conditioning Heating And Pressurizing Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like R-25999.