In an apparatus for selective laser melting and/or laser sintering with a mounting base, that has at least one chamber, wherein the at least one chamber is a building chamber and/or a powder reservoir chamber for a powder, the saving of powder results in an increase in the possible uses of the apparatus, in that the apparatus further comprises at least one fitting element, wherein in operation, the at least one fitting element is located in the at least one building chamber, wherein in a first configuration the at least one fitting element is vertically movable relative to the main body and in a second configuration the at least one fitting element is fixedly connected to the mounting base.