If you need a good overheadstirrer,for almost no money,but still verry relyabel,youll get your self a motor from a windscreen whiper,get an dc trafo,thats ajustible ,and get a teflon stirrpaddle,and your done under 30euro,s.
Mine works for years now,never a problem.
Does not heat up when i use it for 48hours.
But it does not have the advanced shit,a laboratory stirrer has,but is a shitload cheaper,an does the job