dial the key when it‘s only letters?

fahrenheit/celsius table, you will see that there is only one temperature that is the same on both.

mirror the three paths. For example, the leftmost path, that's on number 1 now and goes to M, will then be on the right side, on number 3 and going to L.

roll a physical tube. Just check where the lines of the letters connect to on the opposite side.

which letters of the text above you need to read, from top to bottom.

barcode also has numbers below.

numbers show the meaning of the white gaps.

l8 - late, light?
g8 - gate?
ant1 - just the letter A?
butterfly8 - butterflight? or just the letter L?
f8 - fight?
fishC& - fish can't?
m8 - might? mate?
wasp4/bee4 - before?
eyel& - island?

Celsius or Fahrenheit.

only one temperature where those two are the same.