Abstract: Apparatus for refilling compressed-gas bottles, having a threaded connector and valve, especially for small gas bottles. A cartridge holder serves to hold jacket-less, oxygen-yielding cartridges whose oxygen can be transferred from the interior of the cartridge holder to the compressed-gas bottle. To solve the problem of achieving the inexpensive refilling of compressed-gas bottles with little oxygen loss, without endangering the operator by the development of undue heat, the cartridge holder of the invention preferably is made in the form of a substantially closed pressure body surrounding the cartridge as closely as possible. Also, a threaded connection is provided for the installation of the pressure body on the compressed-gas bottle. A gas passage serves for the transfer of the oxygen to the compressed-gas bottle connector. Furthermore the pressure body comprises cooling ribs and a heat guard with ventilation openings communicating with grooves between the cooling ribs.