Dual-material block nozzle for cooling a strand, preferably having a billet or pre-block cross section, in a continuous casting machine, having - substantially cuboid base body, wherein the base body comprises - a base face; - an end face; - a plurality of lateral faces; - a first connector for a liquid cooling medium; - a second connector for a gaseous cooling medium, wherein the first and the second connector (5, 6) are disposed on the base face; - a mixing chamber for thoroughly mixing the liquid cooling medium with the gaseous cooling medium, wherein the mixing chamber by way of a first duct is connected to the first connector, and by way of a second duct is connected to the second connector; and - a third connector for releasably fastening a spray nozzle to the base body, wherein the third connector by way of a third duct is connected to the mixing chamber; as well as - at least one groove or a bore for receiving a fastening means for releasably fastening the base body to a flange; wherein the size of the surfaces of at least two faces, preferably of at least three faces, from the group of the end face and the flat lateral faces in relation to the cuboid initial state of the base body are reduced by at least 10% by a rounding or a chamfer of in each case one edge between the end face and a lateral face, on account of which the bearing faces for scale on the surfaces are likewise reduced. - substantially cuboid base body, wherein the base body comprises - a base face; - an end face; - a plurality of lateral faces; - a first connector for a liquid cooling medium; - a second connector for a gaseous cooling medium, wherein the first and the second connector (5, 6) are disposed on the base face; - a mixing chamber for thoroughly mixing the liquid cooling medium with the gaseous cooling medium, wherein the mixing chamber by way of a first duct is connected to the first connector, and by way of a second duct is connected to the second connector; and - a third connector for releasably fastening a spray nozzle to the base body, wherein the third connector by way of a third duct is connected to the mixing chamber; as well as - at least one groove or a bore for receiving a fastening means for releasably fastening the base body to a flange; wherein the size of the surfaces of at least two faces, preferably of at least three faces, from the group of the end face and the flat lateral faces in relation to the cuboid initial state of the base body are reduced by at least 10% by a rounding or a chamfer of in each case one edge between the end face and a lateral face, on account of which the bearing faces for scale on the surfaces are likewise reduced. - a base face; - an end face; - a plurality of lateral faces; - a first connector for a liquid cooling medium; - a second connector for a gaseous cooling medium, wherein the first and the second connector (5, 6) are disposed on the base face; - a mixing chamber for thoroughly mixing the liquid cooling medium with the gaseous cooling medium, wherein the mixing chamber by way of a first duct is connected to the first connector, and by way of a second duct is connected to the second connector; and - a third connector for releasably fastening a spray nozzle to the base body, wherein the third connector by way of a third duct is connected to the mixing chamber; as well as - at least one groove or a bore for receiving a fastening means for releasably fastening the base body to a flange; wherein the size of the surfaces of at least two faces, preferably of at least three faces, from the group of the end face and the flat lateral faces in relation to the cuboid initial state of the base body are reduced by at least 10% by a rounding or a chamfer of in each case one edge between the end face and a lateral face, on account of which the bearing faces for scale on the surfaces are likewise reduced.