The "resistance" the device offers to the penetration of solids and liquids is indicated by the abbreviation IP (International Protection) followed by 2 digits of which the first indicates the degree of protection against solid and the second against liquid substances.

First digit (solids):

X not relevant

0 not protected

1 protected against penetration of hard objects greater than 50 mm

2 protected against penetration of hard objects greater than 12 mm

3 protected against penetration of hard objects greater than 2.5 mm

4 protected against penetration of hard objects greater than 1 mm

Second digit (liquid substances):

0 not protected

1 protected against water droplets falling vertically downwards

2 protected against water falling down with an angle of max. 15 °

3 protected from rain

4 protected against splashes