Below are Lufkin's REPLACEMENT blades. These will fit any frame so long as the new blade matches the width of the existing frame.
Lufkin's terminology can be a bit confusing if you're new to gauging tapes. Essentially, Lufkin calls their tapes BLADES. And, Lufkin's word 'Tape" describes a frame with a blade in it.
Some blades use a chrome clad finish, which makes reading colored fluids easier. Other blades use Lufkin's "Nubian" (black) coating so thnner fluids are easier to read, especially in bright sunlight. Blades with the "DD" designation means they're 'double-duty' (the blade is good for colored and clear-thin oils). They do this by making the "DD" blade nubian on one half and polished on the other. "DD" blades are the best of both worlds.
To select a replacement 'blade', just match the width of the blade to the frame you own. Then just decide on the style (SAE or Metric, DD or all nubian or all polished, etc). Be aware that the Bobs (the weighted device at the end of the tape) do not come with replacement blades.
Lastly, the Lukin CN1290 thru 1295 Atlas Chrone Clad gauging blades fit any Lufkin 1/2" gauging tape's frame. The other sizes fit the non-Atlas width frames.