Use of a cage for producing extinguishing foam from an extinguishing fluid containing foaming agent and a sprinkler, comprising - an extinguishing fluid outlet opening, - a spray plate located in the axial direction opposite the extinguishing fluid outlet opening and having a base surface and an outer diameter (d 1) and - a cylindrical interspace which is formed between the base surface of the spray plate and the extinguishing fluid outlet opening, of which the diameter corresponds to the outer diameter (d 1) of the spray plate and of which the height (h 1), starting from the centre of the base surface, corresponds to the distance to the extinguishing fluid outlet opening, characterized in that the cage encases the said cylindrical interspace between the base surface of the spray plate and the extinguishing fluid outlet opening, and wherein the cage a) has sieve openings with a diameter between 1.00 mm and 7.00 mm and/or lattice openings with a width between 1.00 and 7.00 mm and a length between 2.00 mm and 9.00 mm, preferably formed by an expanded mesh, b) encases the aforesaid cylindrical interspace between the base surface of the spray plate and the extinguishing fluid outlet opening and has dimensions which permit the said interspace to be encased as follows, radially with a height (h 2) and a width (d 2): - the height (h 2) of the cage corresponds to at least 0.2 times the outer diameter (d 1) of the spray plate, - the inner diameter (d 2) of the cage, alternatively the non-circular minimum spacing between the opposite inner sides of the cage, at the height of the spray plate corresponds to at least the outer diameter (d 1) of the spray plate. - an extinguishing fluid outlet opening, - a spray plate located in the axial direction opposite the extinguishing fluid outlet opening and having a base surface and an outer diameter (d 1) and - a cylindrical interspace which is formed between the base surface of the spray plate and the extinguishing fluid outlet opening, of which the diameter corresponds to the outer diameter (d 1) of the spray plate and of which the height (h 1), starting from the centre of the base surface, corresponds to the distance to the extinguishing fluid outlet opening, - a spray plate located in the axial direction opposite the extinguishing fluid outlet opening and having a base surface and an outer diameter (d 1) and - a cylindrical interspace which is formed between the base surface of the spray plate and the extinguishing fluid outlet opening, of which the diameter corresponds to the outer diameter (d 1) of the spray plate and of which the height (h 1), starting from the centre of the base surface, corresponds to the distance to the extinguishing fluid outlet opening, a) has sieve openings with a diameter between 1.00 mm and 7.00 mm and/or lattice openings with a width between 1.00 and 7.00 mm and a length between 2.00 mm and 9.00 mm, preferably formed by an expanded mesh, b) encases the aforesaid cylindrical interspace between the base surface of the spray plate and the extinguishing fluid outlet opening and has dimensions which permit the said interspace to be encased as follows, radially with a height (h 2) and a width (d 2): - the height (h 2) of the cage corresponds to at least 0.2 times the outer diameter (d 1) of the spray plate, - the inner diameter (d 2) of the cage, alternatively the non-circular minimum spacing between the opposite inner sides of the cage, at the height of the spray plate corresponds to at least the outer diameter (d 1) of the spray plate. - the height (h 2) of the cage corresponds to at least 0.2 times the outer diameter (d 1) of the spray plate, - the inner diameter (d 2) of the cage, alternatively the non-circular minimum spacing between the opposite inner sides of the cage, at the height of the spray plate corresponds to at least the outer diameter (d 1) of the spray plate.