Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BN-4-0-51-5-L11 ASSY 51-CQQ3-5 found under Valve Butterfly by Universal Industrial Products Co. The National Stock Number assigned to this part is 4820012846894, 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 BN-4-0-51-5-L11 ASSY 51-CQQ3-5.