Deel design varies among cultures, ethnic groups and time periods to a certain degree. There are even distinct variations among different Mongol tribes mostly on the design of the upper chest opening edges. For instance the Khalkha Mongol deel opening edges are round while a Buryat deel's is square. It can also vary among other tribes such as Chakhar, Torguud, and Uzemchin. Deels are designed for different occasions and environments. The design also varies due to function. There are deels for ceremonies like weddings and holidays and deels for daily wear. Deels for special occasions have their outer layer made of silk while the common deels are usually made of wool, cotton and other relatively inexpensive materials.