Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ER20-12-4 found under Valve Ball by Richards Industries Value Group. The National Stock Number assigned to this part is 4810014956573, and the Federal Supply Class is 4810 Valves Powered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like ER20-12-4.