Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number D937BK found under Parts Kit Thermo Va by Insinger Machine Company The. The National Stock Number assigned to this part is 4820008729088, 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 D937BK.