How waterproof is the USG-2
The internal electronics of the USG-2 are potted and sealed to provide a high level of water/ingress protection. The high quality, shielded USB lead included with the USG-2 also provides a similar, high level of water protection when mated with the high retention USB receptacle.
The pluggable screwless connector meets all requirements in accordance with EN 60068-2-11:
If the device is going to be used in an environment where it is going to be subjected to direct contact with water splashes etc. then it is recommended as a preventative measure that silicone grease (or dielectric grease) is used.