here ya go mate, i use the insulated ducting on the output side of the cooltube because the air being blown past the bulb warms up standard duct and adds heat to the tent, you probably wont have that prob with the 250w and isnt necessary on the input side of the cooltube because this air is cool from the fan, the last pic shows how i mount my fan to the top of the tent, rvk fans have three threaded mounting posts to accomodate the new style mouting bracket, just get some standard screw in hooks from b&q or somewhere and screw them into two of the mounting posts on the fan, then you just need to bend the hooks out slightly with some pliers and your fan will hook straight onto the budboxes roof support bar and the filter i just support with a length of washing line tied between the centre support bar and the outer support bar, and i just slide the washing line support down the bar when i need to change the filter.