Original dipstick or in Ford speak "Indicator - Oil Level" for FMX automatic transmissions. Application for 1969 - 1972 Mercury Cougar and Ford Mustang with 351 and FMX automatic transmissions, code "X" on your door data plate. Sometime during 1972 Ford changed to C9AP-7A020-C. Same dip stick, but with a longer handle.
Ford master part number C9OZ-7A020-A, Ford casting # C9OP-7A020-A.