SNK809 Size?

Hey guys, we all know and love the classic Seiko 5 SNK809, but I’m not sure of the case size. What is the case diameter? I’ve been trying to look it up and I’m seeing 36, 37, and 38mm. Which is it? And is the water resistacne really just 50m?

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I owned one back in the day. If I remember correctly it was 37mm. It wears small but it is a great little watch. The WR is actually 30m.