Abstract: An improved air filter panel of the type having a fibrous filter batt and a circumferential support frame surrounding the batt, the frame having an axially extending frame element, the frame element being folded transversely to form frame sidewalls, the sides of the batt being connected to the sidewalls of the frame, the ends of the folded frame element being fastened together to secure the batt in place within the surrounding sidewalls, the improvement comprising an improved frame end fastening means, the means comprising a tab connected at a fixed end thereof to the sidewall of the support frame adjacent one end of the frame element, the tab having a neck portion at the fixed end and a head portion adjacent a free end thereof, the head portion being connected along a portion of a following edge thereof to the neck portion, the remaining unconnected portion of the following edge providing a flange portion, and a slot in the sidewall adjacent the end of the frame element opposing the tabbed end, the slot bein