I so far have used my new machine once & discovered the use & difference between the cold & hot switch my eyesight is not good. Nut there is this little black lever in the back & I don't know what it is for. You can tress it up & down but I have know idea what it does :&: it is hard for ne to read the instructions. Like I say I have played w/the cold & hot & have an understanding how that works & it does the job well. Like. I would recommend is enough to use & price is right..