What does it mean?

[grex]

Hi to all you experts ,

I'm a super newbie here and trying to understand more. Why do some of the watches have Swiss made below the 6 o'clock mark while some have something like Swiss T< 45 kinda wordings? Whats the difference?

[ejaan]

This is referring to the chemical applied to the hands and hour markers for luminescence. In the early days, way before most of us were born , Tritium was used as the luminous material. Tritium is radioactive and so the manufacturer is required to indicate the radioactive emission of the watch. I believe the maximum limit allowable is 25 millicurie. Thus, SWISS T < 25 indicates that the amount of chemical used on the watch, emits an amount of less than 25 millicurie of Tritium.

Later, Tritium was replaced with Luminova as the source of luminescence. Luminova is organic and non-radioactive. Being such, the manufacturer is not required to indicate its radioactive emission. In most cases, SWISS MADE indicates that Luminova is the luminous material.

[louie]

another lesson learnt! cheers to bro ejaan!

[grex]

What does it mean

That's amazing.... Good knowledge... So it's also an indication of the age of the timepiece right? My friend got a piece of explorer 2 with that marking, wanting to sell it to me, but I want to know the age and a reasonable price before I decide..... Dear experts, any advise on which year of production it might be?

[mokwai]

sounds like history class, but i like it.

[ejaan]

To determine the year of production for the watch it is best to refer to the serial number. This forum has a list of watch's production year with their corresponding serial number.

[Taurus75]

That's amazing.... Good knowledge... So it's also an indication of the age of the timepiece right? My friend got a piece of explorer 2 with that marking, wanting to sell it to me, but I want to know the age and a reasonable price before I decide..... Dear experts, any advise on which year of production it might be?

Yes, the "SWISS-T< 25" or the "SWISS MADE" are indications of the luminous material used on the watch but u did not state exactly which of it that your friend's watch comes with in your post.

"SWISS - T < 25" markings indicate that the luminous material on the watch is Tritium and it was used up the year 1998. Somtime from 1998 to 2000, the luminous material changed to Superluminova and this was reflected by the markings of "SWISS". From 2000 onwards, superluminova continued to be used but the markings changed again to "SWISS MADE".

so from the changes of the luminous material that Rolex employed, one can have a rough gauge of the age of the watch. But evidently, those that comes with the "SWISS-T< 25" markings would include many earlier series and u may not be able to postively narrow down the ages of the watch without the series indication. So as others have suggested, it is better to just ask your friend for the series of the watch to have a more accurate gauge on the price to pay.

[ejaan]

sounds like history class

That boring huh? I used to sleep during history classes.

[grex]

what does it mean

Thanks guys for the info. Thats very informative! Well, his watch came with oyster lock, so I reckon it should be around 99 or 2000's production... As he bought it preowned, no cert no box so he dunno the serial no. Thanks for the advises,i've learnt something new..

[deadbench]

This is referring to the chemical applied to the hands and hour markers for luminescence. In the early days, way before most of us were born , Tritium was used as the luminous material. Tritium is radioactive and so the manufacturer is required to indicate the radioactive emission of the watch. I believe the maximum limit allowable is 25 millicurie. Thus, SWISS T < 25 indicates that the amount of chemical used on the watch, emits an amount of less than 25 millicurie of Tritium.

Later, Tritium was replaced with Luminova as the source of luminescence. Luminova is organic and non-radioactive. Being such, the manufacturer is not required to indicate its radioactive emission. In most cases, SWISS MADE indicates that Luminova is the luminous material.

as highlighted by bro ejaan, swiss made = luminova only applies to recent models from 1987 onwards...

watches long before the SWISS T(estimate 1940s?) are also labelled SWISS or SWISS MADE ...which are still tritrium.. pls correct me if im wrong..

so the year counts too...

[ejaan]

As I have stated earlier "In most cases, SWISS MADE indicates that Luminova is the luminous material". The reason I said that is because Rolex watches manufactured before the 1950s used Radium for luminescence and have the the word SWISS MADE on the dial. For watches of this time period it simply meant that the watch was made in Switzerland.

OK, no more boring history lesson. Let's get on with our life.

[BasT]

Rolex used radium up until the early 60's after which they switched to tritium. At least in their Submariners, so I guess the other models as well.

No worries if you do not have the certificate, the serial number is engraved on the watch between the lugs. Just remove the bracelet and you will have a good idea on how old the watch is.