I wanted an all-in-one nozzle so that I wouldn't have to constantly change it. I didn't notice in the description that it was for the k5 series, but when I received it, I saw it. I have a nozzle from the k2 series and after buying this one, I decided to try it. Excellent nozzle, the two out of the three functions (fan and rotary) are great, and if you also listen to the sound it makes every time you change the setting, you can use it with your eyes closed. It is ergonomic, powerful, and water-efficient