Plain white ones are often reserved for festivals and special occasions. Those intended for everyday use may have a black velvet lining. In the Turkic cultures of central Asia, they have a sharp tapering to resemble a mountain, rather than the cyndrical kalpaks of Turkey.
White items are typically reserved for celebrations and special events. Everyday versions might be lined with black velvet.  In Central Asian Turkic cultures, these objects have a pointed shape that resembles a mountain, unlike the cylindrical kalpak designs found in Turkey.