My understanding is this
First digit "X" means that it don't have any protection against hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects (sand, duct ..)
Second digit is "7" means "immersion up to 1 m" is okay". Detail explanation is "Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion)."
However this is just the factory specifications...