I already aware of the "T" marking on Swiss Made watches. But when i was looking at this link:
it seems like the "T" is optional
So, does it mean the watch marker doesn't have to put the "T" marking on the watch, but its optional. which in turn will means there may be watches with tritium (or promethium) without the marking?ISO 3157 Standard allows an optional marking for timepieces emitting less than a certain value.
Also, I wonder if the watches with "T" marking does in fact emit less radiation energy than the ones with "T<25"
The indication "T Swiss made T" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 227 MBq (7,5 mCi).The indication "Swiss T<25" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 925 MBq (25 mCi).