The Sndway rangefinders are colour coded:
Green - 600m rated
Orange - 1000m rated
Blue - 1500m rated
I would read that a 1500m version is reliable to 750m as the rating will be for very ideal conditions.
Note Sndways are IP54 rated, that is:
Dust - Protected from limited dust ingress.
Liquids - Protected from water spray from any direction, limited ingress protection.
In other words, should be OK to take out and use in the wind and rain, but carry them covered and don't go swimming.
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