Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 16776 MFG-00052-2221AT found under Valve Hand Bypass by Hardigg Industries Inc. The National Stock Number assigned to this part is 4820015404802, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 16776 MFG-00052-2221AT.