The study of nuclides far from the valley of stability in recent years, with various spectroscopic methods, sets new demands for the handling of the ion beams. A relative old technique that was first proved to be feasible by Paul and his coworkers has been revived by using electromagnetic fields to prevent the low energy ions from losing in the gas. In the past few years, emittance improvement of low-energy radioactive ion beams has gained a lot of interest and several devices for an emittance improver and buncher have been constructed. The study of nuclides far from the valley of stability in recent years, with various spectroscopic methods, sets new demands for the handling of the ion beams. A relative old technique that was first proved to be feasible by Paul and his coworkers has been revived by using electromagnetic fields to prevent the low energy ions from losing in the gas. In the past few years, emittance improvement of low-energy radioactive ion beams has gained a lot of interest and several devices for an emittance improver and buncher have been constructed.