Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5873 found under Seat Valve by Nicholson Steam Trap Inc. The National Stock Number assigned to this part is 4820012958540, 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 5873.