Abstract: Filter for air and intended for use in wet environment of folded filter material (1) that is held together by glue strips (2,3) on the front and rear side of the filter material. The glue strings on the front side of the filter are interrupted at the bottom of the folds turned forwards so that transport channels (4) for water (5) are obtained at each forwards turned fold. Furthermore the filter folds are oriented vertically to facilitate for the water to run off.