We have searched for sheets large enough to fir our king mattress. Very few manufacturers actually make a top sheet for oversized (deep) mattresses that actually will "tuck in" and stay. Thomas Lee sheets are the largest size we have found, including the expensive brand we have been using for the last several years. It only stands to reason that the quality of the cotton and the crispness of the percale would only exist in a manufacturer that will add the extra inches needed for every mattress. Outstanding sheets. Expensive, but not considering what they deliver.