Instruct: Classify the given review as either positive or negative.
Query: Warped on first use

Using for the first time I followed the labeled directions and set the two burners and bridge element at medium low heat and the griddle pan (which initially sat perfectly flat on the stove top) warped from corner to corner creating a wobble of about half an inch by the time it was warm enough to brown a grilled cheese sandwich. Not terribly effective for a flat top range. When cooled the pan regained some of it's original shape but still has about a quarter of an inch of wobble from corner to corner. Very disappointing. The label indicated that it was safe up to 350 degrees but mine warped well below that temperature. Too bad, it's a nice looking piece of cookware and the padded handles are a nice feature but worthless if you can't use it.