Mick
Is this what your talking about? These were already installed when I got my scope. I haven't had a need to use them (apart from hooking them up to a battery to see if they work). They are configured to blow across the mirror face. At the moment thier wires just protrude out of the bow. I am planning a more permenant arrangement with switches soon, as this might get me to lug the big whoer outside at short notice if the cool down time is significantly reduced. Might get around to testing out some theories