The QLS (Quick Lock Standard) is a quick locking replacement for the threaded interface of the popular SMA connector. Designed and manufactured jointly by German-based RF and Microwave component suppliers Telegartner and IMS Connector Systems, this new connector emerged in 2006 as an answer to some of the shortcomings of the original QMA: Improvements in this version include: A strong locking mechanism that makes it very difficult to accidentally detach the connector and a longer life-span.
References
QLS connector Wikipedia(Text) CC BY-SA