I just read on a post on here what people suggested was needed,not used xtel yet (it never came until over a week after the slx) I suppose it is a back up,and people seemed to say they used 17' most of time and 25' for over conny's etc,now i have got it i don't really see the point of having 2!!!! I think i will just end up using the slx all the time(but we shall see).I got a extra brush(which i ordered later) for conny roofs and guttering because i was worried i might knacker the other one up with tfr