Vent filter and radio remote unit

A Radio Remote Unit comprising a vent filter, wherein the vent filter comprises:

• a first member comprising a first body having a ventilation path extending through the first body, an inner wall protruding from an end of the first body and constituting a ventilation hole which is communicated with the ventilation path, and an outer wall protruding from the end of the first body and constituting a gap between the inner wall and the outer wall;
• and
• a second member comprising a second body and at least one enclosure wall protruding out from the second body, wherein at least one of the at least one enclosure wall is located outside the outer wall and surrounding the outer wall;
• wherein both the inner wall and the outer wall have at least one first groove at an end facing away the first body and each of the at least one enclosure wall has at least one second groove at an end facing away the second body.