Thanks Mark,

I've had a couple of Sinns and really liked them- a 757S and a U1 Black. Am tempted by the EZM1...

: The "Ar" (note lower case r) on the later watches refers
: to the watch being filled with argon to prevent moisture getting
: in - argon is denser than air but inert. It's nothing to do with
: the lume material, unlike the 3H markings. The Ar watches have
: Superluminova lume, so don't need any special markings on the
: dial because of it, because it's not radioactive.

: The early EZM2s used tritium, though later watches are marked Hydro
: UX and are filled with silicone oil (the EZM2 is the dive watch
: application, so I guess it makes sense to go a different route
: than for the special forces and police models). The EZM3 is an
: Argon-filled watch too. EZM4 is the emergency services model,
: not sure about that one - I think it's just plain Superluminova
: without being filled with anything exotic!