The Ingress Protection (IP) rating defines the resistance of an enclosure against the intrusion of solids and liquids. IP ratings are represented by the letters IP followed by two digits.
First Digit: Solids
The first digit indicates the level of protection that the enclosure provides against solid objects and is rated on a scale from 0 (no protection) to 6 (no ingress of dust).
No protection.
Protected againts a solid object greater than 50mm such as a hand.
Protected againts a solid object greater than 12.5mm such as a finger.
Protected againts a solid object greater than 2.5mm such as a screwdriver.
Protected againts a solid object greater than 1mm such as a screw or wire.
Dust protected. Limited ingress of dust permitted. Will not interfere with operation of the equipment 2 to 8 hours.
Dust tight. No ingress of dust. 2 to 8 hours.
Second Digit: Liquids
The second digit indicates the level of protection that the enclosure provides against liquids and uses a scale from 0 (no protection) to 9 (high-pressure hot water from different angles).
No protection.
Protected against vertically falling water drops.
Protected against vertically falling water drops with enclosure tilted up to 15 degrees from the vertical.
Protected against spraying water up to 60 degrees from the vertical.
Protected against water splashes from all directions.
Protected against water jets.
Protected against powerful water jets.
Protected against the effects of immersion in water between 15cm and 1m for 30 minutes.
Protected against the effects of immersion in water for long periods.
Protected against high pressure and temperature water jets.
Referenced as IP69K
For more details, visit the International Electrotechnical Commission (IEC) website.