We claim, The ornamental design for a cigarette filter, as shown and described.
1.-2. Cigarette filter
3.-4. Front part of cigarette filter
1.1 : Perspective
1.2 : Perspective
1.3 : Front
2.1 : Perspective
2.2 : Perspective
2.3 : Front
3.1 : Perspective
3.2 : Front
4.1 : Perspective
4.2 : Front
Designs 1 and 2 relate to a cigarette filter and designs 3 and 4 relate to a front side of a cigarette filter; the designs show the shape of an air opening provided in an end cap of the cigarette filter; for designs 1 and 3, the shape of the air opening resembles to a flower with six petals; for designs 2 and 4, the shape of the air opening resembles to a leaf with seven regularly arranged lobes.
The broken lines in the drawings illustrate portions of the cigarette filter which forms no part of the claimed design.