There are international standards developed by the International Electrotechnical Commission (IEC) to designate water resistance and dust resistance. These standards are designated by an "IP" followed by 2 numbers that specify the environmental protection of enclosures around electronic equipment. There are specific tests that must be passed to claim the rating. IP stands for Ingress Protection. The first number refers to the protection against solid objects - dust for example. The second number refers to the protection against liquids - usually water.

The Laserometer is rated IP67.

6 = Totally protected against dust.

7 = Protected against immersion for 15 cm to 1 m (5.9 to 39.4 inches) for a duration of 30 minutes.

If you do not see these standards in the specification of products, it's likely that they do not meet those standards.