Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number S577-1 found under Life Preserver Mk3c by Switlik Parachute Company Inc. The National Stock Number assigned to this part is 4220005641578, and the Federal Supply Class is 4220 Marine Lifesaving And Diving Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like S577-1.