This paper provides a detailed overview of the key technology features of the new 5G/NR radio-access technology, the first release of which has recently been published by 3GPP release 15, of the NR specifications finalized by the end of 2017. This first release is limited to non-standalone NR operation, implying that NR devices rely on LTE for initial access and mobility. The final release-15 specifications, to be available in June 2018, will also support stand-alone NR operation. The difference between stand-alone and non-standalone operation is primarily affecting higher layers and the interface to the core network; the basic radio technology is the same in both cases. This paper will give a detailed overview of the NR radioaccess technology with focus on the key features that distinguish it from 4G LTE.