A cooler for electric and/or electronic components with a cooling body including a first flat outer wall and a second flat outer wall at a certain distance from each other and each creating a cooling area. There are cavities between the outer walls on the inside of the cooling body, creating a cooling channel connecting an inflow with an outflow through which a liquid cooling agent can flow. The cooling channel between inflow and outflow runs completely on the inside of the cooling body, and the cooling body is made up of a first part and a second part. The first part has the first outer wall, and at least the first part has a first set of indentations on a first inner wall opposite to the first outer wall, and wherein those indentations are closed off by the second part on the wall opposite of the first outer wall when the cooling body is assembled, thus creating the cooling channel. The course of the cooling channel and/or the arrangement of the cooling section or the cooling sections in the respective application case for which the cooler was designed is adapted to the cooling needs at the first outer wall and/or the second outer wall.