Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number F40 41U ALTO found under Lamp Fluorescent by Philips Electronics North American. The National Stock Number assigned to this part is 6240014612767, and the Federal Supply Class is 6240 Electric Lamps. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like F40 41U ALTO.