They fit mattresses up to around 16 inches deep. A lot of mattresses are pretty big these days and we feel this is a good universal size that fits most mattresses.If you're looking for very soft sheets you have found them! they're breathable, cool and super silky soft.These are made of the highest quality double brushed microfiber yarns. The virtually weightless wonder of CGK unlimited sheets will have you coming back for more.These are some of the softest and most affordable sheets you’ll ever find. They are way softer than other cotton sheets and at a fraction of the cost.