Abstract: A chimney cap for installation on a chimney, comprising a lid assembly, a bracket for supporting the lid assembly, and revolving clamps pivotally connected to the bracket for releasable attachment to various dimensions of chimney flue tiles. The clamps are pivotable for rotation between a first position for accommodating a first dimension of chimney flue tiles and a second position for accommodating a second dimension of chimney flue tiles, the second dimension being larger than the first dimension. The clamps each comprise at least two oppositely disposed spring loaded cam action toggles for gripping opposite sides of the chimney flue tiles irrespective of the thickness of the tiles.