Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B20-03099 found under Seat Valve by Tyco Fire Products Lp. The National Stock Number assigned to this part is 4820008846480, 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 B20-03099.