@JimInOz Tried the mini geiger counter on the phone and it seems to pick up radioactivity on my 1920s Omega traveling clock with loads of radium and a Omega www military watch which the counter went to about 8-10μSv/h, then my 5508 with exclamation dial around 5μSv/h. I can assume it picks up and works ok and pass on to my watch maker.
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