Bondo 762 Bondo-Hair Long Strand Fiberglass Reinforced Filler Quart Can - 2 lbs
It's all in the name.  Formulated with up to inch-long strands of chopped fiberglass, Bondo® Hair repairs 1" rust holes, shattered fiberglass, and dents where extra strength is required.  At twice the strength of regular body filler, this filler is great for rebuilding missing pieces or vehicle restoration work.  For your toughest repairs choose Bondo® Hair.