Rocketdyne unused main engine valve flexline bellows of the type used in early production F-1 engines (through Apollo 4). Component is constructed from high alloy stainless steel rated for 3000 PSI, with an inner diameter of 7″ and outer diameter of approximately 9″, and has a highly-polished cover made to keep the bellows from over-expanding and for structural and thermal isolation. Interior has numerous chemically etched inspection stamps, the Rocketdyne part number "NA5-26831-2," and serial number “51 of Lot III.” In fine condition, with original cover connecting bolts replaced due to corrosion. RR Auction COA.