These are the previous generation. They are slowly being replaced by the Q Max series, which adds wireless vs the Q. For the K, they are moving to K Pro(QMK/VIA support), and now the K Max as well.
So, these are popular, if last year’s models being sold.
These are great buys, especially for a Q series, which is an all aluminum construction with plenty of insulating foam…it can make anything sound great.