Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SD20-1-111 found under by Schat Davit. The National Stock Number assigned to this part is 4820171121701, 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 SD20-1-111.