The blue parachrom hairspring

[Mephist]

At what year did Rolex start using the Blue parachrom hairspring in Datejust's?

[padi56]

Originally Posted by Mephist

At what year did Rolex start using the Blue parachrom hairspring in Datejust's?

Don't think anyone would no that as Rolex do not disclose this information, it has a cal 3135 movement and some models have it,and some dont.But no big deal either way as in the real world IMHO I would doubt if you would find little or no difference whatever the hairspring metal was called in the case.No matter the hairspring and its just a hairspring things like accuracy etc come from how well the movement has been regulated.If any watch with any hairspring is badly set up and regulated its simple movement will perform badly.

Cal 3130 base without date, now some later models reported with parachrom.
Cal 3131 parachrom
Cal 3132 parachrom and paraflex shock system
Cal 3135 base with date
Cal 3135 Subc parachrom
Cal 3136 parachrom bleu and paraflex shock system
Cal 3155 base with date & day
Cal 3156 parachrom bleu and paraflex shock system
Cal 3185 base with date and GMT function
Cal 3186 parachrom bleu
Cal 3187 parachrom and paraflex shock system
Cal 4130 Chronograph first Rolex with the Parachom started in 2000 but then a more grey colour now parachrom bleu which is done by some chemical prosses to turn it blue
Cal 4160 parachrom.
Cal 9001 parachrom.

[Alpino]

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The only confirmed info is that it was introduced in DateJust II in 2009 .