Yes there is a filter, it is a cone and if you look at the last pic, inside the large tube there sits the filter. This filter was carried by a company that went out of business and I do not know who makes the filter but I need to find out. It looks like a K&N but is not oiled and has a different filter media. While I do not have flow charts on the filters I do feel that this filter outflows the oil type, of which I have several that are larger. I am thinking that my truck would not perform as well as it does if it did not flow better than the oil type. My present filter is about 5 3/4 inches at the largest point so it is a fair amount smaller than all my other filters.

TJ