Why does this watch have a radiation symbol on its dial?
Before we answer the question directly,
some context.
In the early days of watchmaking in the first half of the 20th century,
some watch dials had luminous paint applied
for easier reading in low light.
But it was later discovered that radium
used in the process was highly radioactive and harmful to humans.
By the mid 1960s, radium was replaced with tritium,
which was far less radioactive and posed little threat to human health.
In this Marathon watch, the tritium used is housed in gas tubes,
with the marking on the dial serving as an indication of its use.
These watches are also provided with a product code
from the Nuclear Regulatory Commission,
seen on the case. Back further,
they’re commonly used by armed forces,
so don’t be scared.
These watches won’t have you growing another limb if you wear them.